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                                   EXHIBIT 99




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                                   EXHIBIT 99

                                  PRESS RELEASE


         FOR IMMEDIATE RELEASE CONTACT:              P. BLAKE DUPUIS
                                                        409-291-2277


                   MITCHAM INDUSTRIES ANNOUNCES TERMINATION OF
              PREFERRED SUPPLIER AGREEMENT WITH INPUT/OUTPUT, INC.

HUNTSVILLE, Texas (April 28, 1999) - Mitcham Industries, Inc. (NASDAQ: MIND)
announced today that Mitcham and Input/Output, Inc. (NYSE: IO) have terminated
their Preferred Supplier Agreement which called for, among other things, Mitcham
Industries to purchase equipment from I/O and I/O to refer rental inquiries to
Mitcham Industries. The Company said that substantial changes within its
marketplace necessitated its decision to terminate the agreement.

Foremost among those changes is the sharp decline in seismic activity and
overall equipment demand due to continued depressed oil and gas prices, reduced
exploration budgets and consolidations of companies in the oil and gas industry.
The Company said that recent increases in oil prices, while encouraging, have
not yet countered these trends.

"Our immediate goal is to preserve the strength of our company throughout this
downturn," said Billy F. Mitcham, Jr., Mitcham Industries' Chairman and CEO. "In
view of the dramatic changes in our operating environment this past year, we
believe it would be imprudent for our company to make substantial outlays for
equipment that might well be idle for a considerable period of time."

"We remain committed to providing our customers with the finest seismic
equipment available," Mitcham said. "And we have the most advanced seismic
systems and related equipment on the market ready to meet their needs."

Commenting on the company's future relationship with Input/Output, Mitcham said,
"We value our long-standing relationship with Input/Output and look forward to
remaining a good customer in the future."

Mitcham Industries Inc. is the leading independent company specializing in the
leasing of 3-D seismic equipment to the oil and gas industry. Mitcham also sells
new and "experienced" seismic equipment.

                                     M O R E



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This press release contains forward-looking statements within the meaning of
Section 27A of the Securities act of 1933 and Section 21E of the Securities
Exchange Act of 1934. All statements other than statements of historical facts
included herein, including statements regarding potential future demand for the
company's products and services, the company's future financial position and
results of operations, business strategy and other plans and objectives for
future operations, are forward-looking statements.

Although the company believes that the expectations reflected in such
forward-looking statements are reasonable, it can give no assurance that such
expectations will prove to have been correct and actual results may differ
materially from such forward-looking statements. Important factors that could
cause or contribute to such differences include: uncertainty of the oil and gas
industry and demand for services; dependence upon additional lease contracts;
customer concentration and credit risk; industry consolidation; the risk of
technological obsolescence of the company's lease fleet; vulnerability to
weather conditions and seasonality of results; dependence upon suppliers; risks
related to Year 2000 issues; and other factors which are disclosed in the
company's Securities and Exchange Commission filings, available from the company
without charge. Further, all written and verbal forward-looking statements
attributable to the company or persons acting on its behalf are expressly
qualified in their entirety by such factors.

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