================================================================================

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

                                   ----------


                                    FORM 8-K


                                 CURRENT REPORT


                         PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934


                                   ----------


      DATE OF REPORT (DATE OF EARLIEST EVENT REPORTED): DECEMBER 17, 2003


                               INPUT/OUTPUT, INC.
             (Exact Name of Registrant As Specified In Its Charter)

         DELAWARE                       1-12691                  22-2286646
(State or Other Jurisdiction     (Commission File No.)        (I.R.S. Employer
      of Incorporation)                                      Identification No.)

                             12300 PARC CREST DRIVE
                              STAFFORD, TEXAS 77477
               (Address of Principal Executive Offices) (Zip Code)

                                 (281) 933-3339
              (Registrant's Telephone Number, Including Area Code)

================================================================================




ITEM 5. OTHER EVENTS AND REGULATION FD DISCLOSURE.

         On December 17, 2003, Input/Output, Inc., a Delaware corporation
("IO"), issued a press release pursuant to Rule 135c under the Securities Act of
1933, as amended (the "Securities Act"), announcing that the initial purchaser
of IO's 5.50% Convertible Senior Notes due 2008 had exercised its over-allotment
option and purchased an additional $10 million aggregate principal amount of the
notes. The primary offering of $50 million aggregate principal amount of the
notes closed on December 10, 2003. As a result, the total principal amount of
the notes issued by IO is $60 million.

         The notes bear interest at the rate of 5.50% per annum and are
convertible into shares of IO common stock at a conversion rate of 231.4815
shares of common stock per $1,000 principal amount of notes. This conversion
rate is equivalent to an initial conversion price of $4.32 per share of common
stock, subject to adjustment in certain circumstances.

         The foregoing is qualified by reference to the press release which is
attached as Exhibit 99.1 to this Current Report on Form 8-K, which is
incorporated herein by reference.

         The information contained in this Current Report on Form 8-K, including
the exhibit hereto, is neither an offer to sell nor a solicitation of an offer
to purchase any of the notes or any shares of common stock of IO, and shall not
constitute an offer, solicitation or sale in any jurisdiction in which such
offer, solicitation or sale is unlawful. The notes and shares of common stock of
IO issuable upon conversion of the notes have not been registered under the
Securities Act or the securities or blue sky laws of any jurisdiction and,
unless registered, may not be offered or sold except pursuant to an applicable
exemption from the registration requirements of the Securities Act and
applicable securities laws of any other jurisdiction.

ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS.

         (a)      Financial Statements of business acquired

                           Not applicable

         (b)      Pro forma financial information

                           Not applicable

         (c)      Exhibits

                  99.1     Press release of Input/Output Inc. dated
                           December 17, 2003.

ITEM 9. REGULATION FD DISCLOSURE.

A. LIMITATION ON INCORPORATION BY REFERENCE

         In accordance with General Instruction B.2 of Form 8-K, the information
set forth in this Item 9 shall not be deemed to be "filed" for purposes of
Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), or otherwise subject to the liabilities of that section, nor shall such
information be deemed incorporated by reference in any filing under the
Securities Act or the Exchange Act, except as shall be expressly set forth by
specific reference in such a filing.



B. SUPPLEMENTAL INFORMATION

SCF NOTE AND WARRANT

         Approximately $16 million of the net proceeds from the primary offering
of notes referred to above was applied to repay in full the outstanding
indebtedness under an unsecured promissory note payable by IO to SCF-IV, L.P.
("SCF-IV"), which was scheduled to mature in May 2004. In addition, concurrently
with the closing of the primary notes offering on December 10, 2003, IO issued,
in a privately-negotiated transaction, 125,000 shares of its common stock to
SCF-IV in exchange for SCF-IV's surrender to IO of its warrant to purchase
2,673,517 shares of IO's common stock at an exercise price of $8.00 per share.
This exchange was effected in a transaction exempt from the registration
requirements under the Securities Act.








                                    SIGNATURE

         Pursuant to the requirements of the Securities Exchange Act of 1934, as
amended, the Registrant has duly caused this report to be signed on its behalf
by the undersigned, thereunto duly authorized.

                                            INPUT/OUTPUT, INC.
                                            (Registrant)


                                                    /s/ [Brad Eastman]
                                            ------------------------------------
                                                        [Brad Eastman]
                                            Vice President, Chief Administrative
                                                    Officer and Secretary


Date: December 17, 2003




                                  EXHIBIT INDEX



EXHIBIT NO.        DESCRIPTION
-----------        ------------------------------------------------------------
                
99.1               Press release of Input/Output, Inc. dated December 17, 2003.