Summary: In testimony before a congressional subcommittee, GAO related information concerning foreign countries' opinions of the proposed sale of the National Oceanic and Atmospheric Administration's remote sensing satellite (Landsat) systems. GAO also discussed how those countries use Landsat information. Foreign countries account for about 45 percent of the Department of the Interior's sales of Landsat tapes and photographic images, and they also sell Landsat data received by their ground stations to other countries. The countries use Landsat data primarily for research and development and many have made significant commitments of their government resources to acquire reception equipment. GAO commented that Landsat uses are particularly important for developing countries where less is known about topography and natural resources. Although foreign countries find Landsat useful, they believe that the development of a commercial market is several years away. While other countries were not opposed to commercialization of Landsat, they expressed concerns about: (1) data sales policies contrary to their economic and national security interests; (2) termination of direct satellite transmission which would require expensive ground station alterations; and (3) increased prices which would force reductions in data purchases.