COMMENTS RECEIVED ON 03/12/2021

FROM EDWARD BARTZ

FIDELITY ABERDEEN STREET TRUST (File Nos. 033-43529 and 811-06440)

Fidelity Freedom Blend Income Fund, Fidelity Freedom Blend 2005 Fund, Fidelity Freedom Blend 2010 Fund, Fidelity Freedom Blend 2015 Fund, Fidelity Freedom Blend 2020 Fund,

Fidelity Freedom Blend 2025 Fund, Fidelity Freedom Blend 2030 Fund, Fidelity Freedom Blend 2035 Fund, Fidelity Freedom Blend 2040 Fund, Fidelity Freedom Blend 2045 Fund, Fidelity Freedom Blend 2050 Fund, Fidelity Freedom Blend 2055 Fund, Fidelity Freedom Blend 2060 Fund, Fidelity Freedom Blend 2065 Fund

POST-EFFECTIVE AMENDMENT NO. 138

1.

All funds

“Fund Management” (prospectus)

“Advisory Fee(s)”

“[A different all-inclusive management fee rate is applicable to each class of a fund. For Premier Class, such fee is subject to the expense contract arrangements discussed in greater detail under “Management Contracts – Management-Related Expenses” in the SAI. The difference between classes is the result of separate arrangements for class level services and/or waivers of certain expenses. It is not the result of any difference in advisory or custodial fees or other expenses related to the management of a fund’s assets, which do not vary by class.]”

C:

The Staff requests that we confirm the above paragraph will be included in the 485(b) filing. In addition, the Staff requests that we add disclosure stating that the funds’ Board of Trustees has approved the expense structures of the classes of the funds and has determined that the fee structures do not result in a waiver of investment advisory fees or in cross-subsidization of expenses between classes.

R:

We confirm that the above paragraph will be included in the funds’ 485(b) filing. Further, the following disclosure has been added to the “Fund Services – Fund Management – Advisory Fee(s)” section:

The Board of Trustees has approved the expense structure of Premier Class of each fund, and has determined that the fee struc­ture does not result in a waiver of investment advisory fees or in cross-subsidization of expenses between classes.

2.

All funds

“Fund Summary” (prospectus)

“Fee Table”

Example from Fidelity Freedom Blend Income Fund:

“The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 44% of the average value of its portfolio.”

C:

The Staff requests we disclose that the underlying funds will incur transaction costs.

R:

We believe the disclosure included in the prospectus is consistent with Item 3 of Form N‐1A, which requires that we disclose the relationship between a fund’s transaction costs and a fund’s portfolio turnover rate. The transaction costs of the underlying funds the fund may invest in have no bearing on a fund’s portfolio turnover rate. Accordingly, we have not revised our portfolio turnover disclosure.

3.

All funds

“Fund Summary” (prospectus)

“Principal Investment Strategies”

C:

The Staff requests we add maturity and credit quality policies for the funds’ fixed income

investments.

R:

Each fund’s principal investment strategy is to invest in underlying funds according to a disclosed asset allocation strategy. Because the funds do not have a principal investment strategy to invest in any particular underlying fund with a specific average credit quality or maturity dates, we respectfully decline to include this disclosure in the principal investment strategies section. We will continue to reflect the appropriate risk disclosure according to each fund’s exposure to such instruments through underlying funds.

4.

All funds

“Fund Summary” (prospectus)

“Principal Investment Strategies”

C:

The Staff requests we provide the market capitalization policy for stocks and disclose corresponding

risks if small or mid‐cap stocks will be a principal strategy.

R:

Each fund’s principal investment strategy is to invest in underlying funds according to a disclosed asset allocation strategy. Because the funds do not have a principal investment strategy to invest in any particular underlying fund with a specific market capitalization range, we respectfully decline to include this disclosure in the principal investment strategies section. Note, however, that the Statement of Additional Information includes a brief description of the principal investment policies of each underlying fund, including whether an underlying fund has a specific market capitalization strategy.

5.

All funds

“Fund Summary” (prospectus)

“Principal Investment Strategies”

C:

The Staff questions whether there are emerging markets issuers and, if so, asks that we include

appropriate strategy and risk disclosure.

R:

Each fund’s principal investment strategy is to invest in underlying funds according to a disclosed

asset allocation strategy. Each fund’s principal investment risks disclosure corresponds to each fund’s exposure to specific underlying funds as of a certain date. Because the funds do not have a principal investment strategy to invest directly in emerging markets securities, but rather invest in underlying funds that may have exposure to such securities, we respectfully decline to include this disclosure in the principal investment strategies section and will continue to reflect the appropriate risk disclosure according to each fund’s exposure to such instruments through underlying funds. We note that emerging markets risk is disclosed under “Foreign Exposure” in the Fund Summary, as applicable, and Fund Basics sections of the prospectus.

6.

All funds

“Fund Summary” (prospectus)

“Principal Investment Risks”

C:

The Staff requests we add a separate risk for derivatives.

R:

Each fund believes that the risks associated with investing in derivatives are described in “Issuer‐ Specific Changes” and “Leverage Risk” in the Fund Summary section of the prospectus and, therefore, the addition of a separate risk factor for this type of investment would be duplicative.

7.

Fidelity Freedom Blend 2015 Fund, Fidelity Freedom Blend 2020 Fund, Fidelity Freedom Blend 2025 Fund, Fidelity Freedom Blend 2030 Fund, Fidelity Freedom Blend 2035 Fund, Fidelity Freedom Blend 2040 Fund, Fidelity Freedom Blend 2045 Fund, Fidelity Freedom Blend 2050 Fund, Fidelity Freedom Blend 2055 Fund, Fidelity Freedom Blend 2060 Fund, Fidelity Freedom Blend 2065 Fund

“Fund Summary” (prospectus)

“Principal Investment Risks”

Example from Fidelity Freedom Blend 2015 Fund:

“"Growth" Investing. "Growth" stocks can perform differently from the market as a whole and other types of stocks and can be more volatile than other types of stocks.

"Value" Investing. "Value" stocks can perform differently from the market as a whole and other types of stocks and can continue to be undervalued by the market for long periods of time. ”

C:

The Staff requests we add strategies for growth investing and value investing in the “Principal Investment Strategies” section.

R:

Each fund’s principal investment strategy is to invest in underlying funds according to a disclosed asset allocation strategy. Each fund’s principal investment risks disclosure corresponds to each fund’s exposure to specific underlying funds as of a certain date. Because the funds do not have a principal investment strategy to invest directly in investments that expose the funds to any of the above mentioned risks, we respectfully decline to include this disclosure in the principal investment strategies section and will continue to reflect the appropriate risk disclosure according to each fund’s exposure to such instruments through underlying funds.

8.

Fidelity Freedom Blend 2020 Fund, Fidelity Freedom Blend 2025 Fund, Fidelity Freedom Blend 2030 Fund, Fidelity Freedom Blend 2035 Fund, Fidelity Freedom Blend 2040 Fund, Fidelity Freedom Blend 2045 Fund, Fidelity Freedom Blend 2050 Fund, Fidelity Freedom Blend 2055 Fund, Fidelity Freedom Blend 2060 Fund, Fidelity Freedom Blend 2065 Fund

“Fund Summary” (prospectus)

“Principal Investment Risks”

Example from Fidelity Freedom Blend 2020 Fund:

“Securities Lending Risk. Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, an underlying fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.”

C:

The Staff requests we add a corresponding strategy for securities lending in the “Principal Investment Strategies” section.

R:

Each fund’s principal investment strategy is to invest in underlying funds according to a disclosed asset allocation strategy. Each fund’s principal investment risks disclosure corresponds to each fund’s exposure to specific underlying funds as of a certain date. Because the funds do not have a principal investment strategy to invest directly in investments that expose the funds to securities lending risk, but rather invest in underlying funds that may have exposure to such strategies, we respectfully decline to include this disclosure in the principal investment strategies section and will continue to reflect the appropriate risk disclosure according to each fund’s exposure to such strategies through underlying funds.

9.

Fidelity Freedom Blend 2035 Fund, Fidelity Freedom Blend 2040 Fund, Fidelity Freedom Blend 2045 Fund, Fidelity Freedom Blend 2050 Fund, Fidelity Freedom Blend 2055 Fund, Fidelity Freedom Blend 2060 Fund, Fidelity Freedom Blend 2065 Fund

“Fund Summary” (prospectus)

“Principal Investment Risks”

Example from Fidelity Freedom Blend 2035 Fund:

“Geographic Exposure to China. Because an underlying fund invests a significant percentage in China, the underlying fund's performance is expected to be closely tied to social, political, and economic conditions in China and to be more volatile than the performance of more geographically diversified funds. In addition, because the underlying fund may invest a significant percentage of assets in certain industries, the underlying fund's performance could be affected to the extent that the particular industry or industries in which the underlying fund invests are sensitive to adverse social, political, economic, currency, or regulatory developments.”

C:

The Staff requests we add a strategy for Geographic Exposure to China in the “Principal Investment Strategies” section.

R:

Each fund’s principal investment strategy is to invest in underlying funds according to a disclosed asset allocation strategy. Each fund’s principal investment risks disclosure corresponds to each fund’s exposure to specific underlying funds as of a certain date. Because the funds do not have a principal investment strategy to invest directly in investments that expose the funds to a concentration in China, we respectfully decline to include this disclosure in the principal investment strategies section and will continue to reflect the appropriate risk disclosure according to each fund’s exposure to such instruments through underlying funds.

10.

All funds

“Investment Policies and Limitations” (SAI)

“Concentration”

C:

The Staff requests we add disclosure to the concentration policy to clarify that each fund will consider the concentration of its underlying investment companies when determining compliance with its concentration policy.

R:

We are not aware of any requirement to disclose this practice under Form N‐1A, but acknowledge that to the extent an underlying fund has adopted a policy to concentrate in a particular industry, each fund will take such policy into account in connection with any investment in such underlying fund.