EXHIBIT 99.1

                     INDEPENDENT ACCOUNTANTS' REVIEW REPORT

The Board of Directors and Stockholders Of Input/Output, Inc. and subsidiaries

    We have reviewed the accompanying consolidated balance sheet information of
Input/Output, Inc. and subsidiaries (the Company) as of September 30, 2001, the
related consolidated statements of operations for the three-month and nine-month
periods ended September 30, 2001 and the related statement of cash flows for the
nine-month period ended September 30, 2001. These consolidated financial
statements are the responsibility of the Company's management.

    We conducted our review in accordance with standards established by the
American Institute of Certified Public Accountants. A review of interim
financial information consists principally of applying analytical procedures to
financial data and making inquiries of persons responsible for financial and
accounting matters. It is substantially less in scope than an audit conducted in
accordance with generally accepted auditing standards in the United States, the
objective of which is an expression of an opinion regarding the financial
statements taken as a whole. Accordingly, we do not express such an opinion.

    Based on our review, we are not aware of any material modifications that
should be made to the accompanying consolidated interim financial statements
referred to above for them to be in conformity with accounting principles
generally accepted in the United States of America.

    The financial statements of Input/Output, Inc. as of December 31, 2000, were
audited by other auditors whose report dated February 1, 2001, expressed an
unqualified opinion on those statements.

    As described in Note 12, the Company has restated its balance sheet and cash
flow statement at September 30, 2001 related to the accounting for a previously
reported sale/leaseback of its Stafford facilities completed in August 2001.

                                                  /s/ PricewaterhouseCoopers LLP

Houston, Texas
November 14, 2001, except for the effect of Note 12 for which the date is March
28, 2002