Several methods have been developed for the measurement of gelatinase activity from various tissues using detergent extraction. Gelatin-affinity chromatography has been employed for the large-scale purification of gelatinases from conditioned medium obtained from cultured cells. The objective of this paper was to develop a rapid method whereby gelatinase activity could be extracted from regional brain tissues without tedious, intervening purification steps. After Triton X-100 extraction and gelatin-Sepharose 4B purification of rat brain tissue extracts, two major activities were observed on gelatin zymograms. These were identified as gelatinase A and B using co-migration with astrocyte-derived enzymes and inhibition of activity by tissue inhibitor of matrix metalloproteinase-1 (TIMP-1). The non-ionic detergents, Triton X-100 and 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonate (CHAPS) were equally effective in extracting activities from brain tissue. Little difference in recovery was observed among 0.1, 1 and 10% concentrations of Triton X-100. The method developed here was capable of recovering gelatinase activities from rat brain tissue over a 4-10-fold range using gelatin zymography for the measurement of activity. It is possible that this method may be modified for the measurement of gelatinases in tissues such as biopsy samples of gliomas or astrocytomas or other cancers where gelatinases are thought to play a role in tumor invasion and/or metastasis.