Nine species of the cactus genus Gymnocalycium were cultivated by the Cactus Club of Ostrava. The fresh plants (200-400g of each specimen) were cut into pieces and immediately homogenized in 400-500ml 95% ethanol, left overnight at 5°C, filtered, evaporated to dryness, and the crude extract was processed via acid-base separation. Alkaloids were identified by GC (co-chromatography with reference compounds) and GC-MS. Small quantities of six β-phenethylamine and nine tetrahydroisoquinoline alkaloids were found in the species. The results suggest a potential value for alkaloid profiles in the taxonomy of Gymnocalycium at the infrageneric level.