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                                                                       EXHIBIT 5

                    [KIRKPATRICK & LOCKHART LLP LETTERHEAD]

September 1, 2000


MRV Communications, Inc.
21415 Nordhoff Street
Chatsworth, CA 91311

Re:    Registration Statement on Form S-3
       File No. 333-44534

Dear Sirs:

We have examined the Registration Statement on Form S-3 and Amendment No. 1
thereto, file no. 333-44534 (collectively the "Registration Statement") filed
and to be filed with the Securities and Exchange Commission in connection with
the registration for resale under the Securities Act of 1933, as amended, of
9,016,103 shares of Common Stock, $0.0017 par value (the "Common Stock"), of MRV
Communications, Inc. (the "Company"), consisting of 8,130,548 outstanding shares
of Common Stock of the Company (the "Shares") and options to purchase 885,555
shares of Common Stock of the Company (the "(Option Shares").

We have also examined such other public and corporate documents, certificates,
instruments and corporate records, and such questions of law, as we have deemed
necessary for purposes of expressing an opinion on the matters hereinafter set
forth. In all examinations of documents, instruments and other papers, we have
assumed the genuineness of all signatures on original and certified documents
and the conformity to original and certified documents of all copies submitted
to us as conformed, photostatic or other copies.

On the basis of the foregoing, it is our opinion that (a) the Shares are validly
issued, fully paid and nonassessable shares of Common Stock of the Company and
(b) upon proper exercise and payment of the consideration to the Company
pursuant to the terms applicable option, the Option Shares will be validly
issued, fully paid and nonassessable shares of Common Stock of the Company.

We express no opinion as to the applicability or effect of any laws, orders or
judgments of any state or jurisdiction other than the substantive laws of the
State of Delaware. Further, our opinion is based solely upon existing laws,
rules and regulations, and we undertake no obligation to advise you of any
changes that may be brought to our attention after the date hereof.



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                    [KIRKPATRICK & LOCKHART LLP LETTERHEAD]

MRV Communications, Inc.
September 1, 2000
Page 2

We consent to the use of our name under the caption "Legal Matters" in the
Prospectus, constituting part of the Registration Statement, and to the filing
of this opinion as an exhibit to the Registration Statement.

By giving you this opinion and consent, we do not admit that we are experts with
respect to any part of the Registration Statement or Prospectus within the
meaning of the term expert as used in Section 11 of the Securities Act, or the
rules and regulations promulgated thereunder by the SEC, nor do we admit that we
are in the category of persons whose consent is required under Section 7 of the
Securities Act.


Sincerely,



 /s/ KIRKPATRICK & LOCKHART LLP

Kirkpatrick & Lockhart LLP