UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   FORM 12b-25
                           NOTIFICATION OF LATE FILING

Commission File Number: 000-20841
                       ----------
(Check One):  [ ] Form 10-K and Form 10-KSB   [X] Form 10-Q and Form 10-QSB
              [ ] Form 20-F  [ ] Form 11-K    [ ] Form N-SAR

For Period Ended: June 30, 2001
                 ------------------------
[ ] Transition Report on Form 10-K    [ ] Transition Report on Form 20-F
[ ] Transition Report on Form 11-K    [ ] Transition Report on Form 10-Q
[ ] Transition Report on Form N-SAR

For the Transition Period Ended:

If the notification  relates to a portion of the filing checked above,  identify
the Item(s) to which the notification relates:

PART I - REGISTRANT INFORMATION

                         Swift Transportation Co., Inc.
                         ------------------------------
                             Full Name of Registrant


                            -------------------------
                            Former Name if Applicable

                             2200 South 75th Avenue
            ---------------------------------------------------------
            Address of Principal Executive Office (Street and Number)

                             Phoenix, Arizona 85043
                            -------------------------
                            City, State and Zip Code

PART II - RULES 12b-25(b) and (c)

If the subject report could not be filed without  unreasonable effort or expense
and the registrant seeks relief pursuant to Rule 12b-25(b), the following should
be completed. (Check box if appropriate)

[X]  (a) The reasons  described  in  reasonable  detail in Part III of this form
     could not be eliminated without unreasonable effort or expense;

[X]  (b) The subject annual report,  semi-annual  report,  transition  report on
     Form 10-K, Form 20-F, 11-K, Form N-SAR, or portion  thereof,  will be filed
     on or before the fifteenth  calendar day following the prescribed due date;
     or the  subject  quarterly  report of  transition  report on Form 10-Q,  or
     portion thereof will be filed on or before the fifth calendar day following
     the prescribed due date; and

[ ]  (c) The accountant's  statement or other exhibit required by Rule 12b-25(c)
     has been attached if applicable.

PART III - NARRATIVE

State below in reasonable  detail the reasons why the Form 10-K and Form 10-KSB,
11-K, 20-F, 10-Q and Form 10-QSB,  N-SAR, or other transition  report or portion
thereof, could not be filed within the prescribed period.

On June 29, 2001,  the  Registrant  completed the merger (the  "Merger") of M.S.
Carriers,  Inc. with and into a wholly owned subsidiary of the Registrant.  Upon
completion of the Merger,  M.S. Carriers became a wholly owned subsidiary of the
Registrant.  Due to the complexity of certain  accounting matters related to the
integration  of  M.S.  Carriers  financial  information  into  the  Registrant's
financial statements,  the Registrant is unable to complete its Quarterly Report
on Form 10-Q for the quarter ended June 30, 2001 by the  prescribed  filing date
of 5:30 p.m. EST on August 14, 2001 without unreasonable effort or expense.

PART IV - OTHER INFORMATION

(1)  Name  and  telephone  number  of  person  to  contact  in  regard  to  this
     notification

           William F. Riley III          602              269-9700
           -------------------------------------------------------------
           (Name)                     (Area Code)     (Telephone Number)

(2)  Have all other periodic  reports  required under Section 13 or 15(d) of the
     Securities Exchange Act of 1934 or Section 30 of the Investment Company Act
     of 1940 during the preceding 12 months (or for such shorter period that the
     registrant was required to file such reports), been filed. If answer is no,
     identify report(s).                                          [X] YES [ ] NO

(3)  Is it anticipated that any significant change in results of operations from
     the corresponding  period for the last fiscal year will be reflected by the
     earnings statement to be included in the subject report or portion thereof?
                                                                  [X] YES [ ] NO

If so, attach an explanation of the anticipated change,  both narratively,  and,
if  appropriate,  state the  reasons  why a  reasonable  estimate of the results
cannot be made.

                         Swift Transportation Co., Inc.
                  --------------------------------------------
                  (Name of Registrant as Specified in Charter)

has  caused  this  notification  to be signed on its  behalf by the  undersigned
hereunto duly authorized.

Date: August 14, 2001                     By: /s/ William F. Riley III
                                             -----------------------------------
                                             William F. Riley III
                                             Senior Executive Vice President and
                                             Chief Financial Officer

                                     Annex A

For the reasons stated in Part III to this Form 12b-25,  the Company's Form 10-Q
for the quarter  ended June 30, 2001  cannot be filed by the  prescribed  filing
date of 5:30 p.m. EST on August 14, 2001. The Company  previously  disclosed its
financial  results for the quarter  ended June 30, 2001 in a press release dated
July 26, 2001. The results of operations set forth in the press release  reflect
the merger with M.S.  Carriers,  Inc.,  which was completed on June 29, 2001 and
accounted  for as a "pooling of  interests."  The press  release  discloses  (i)
revenues of $535.6 million and $1.045 billion for the three and six months ended
June 30, 2001,  respectively,  compared to revenues of $500.3 million and $958.9
million for the  corresponding  periods in the prior year,  (ii) net earnings of
$10.5  million  and $12.7  million  for the three and six months  ended June 30,
2001, respectively,  compared to net earnings of $22.7 million and $38.0 million
for the same three and six month periods in 2000.