Isozymes have been used as genetic markers to characterize seven Spanish cherimoya (Annona cherimola Mill.) cultivars. Fifteen enzyme systems were analyzed. Ten varied [aconitase (ACO, EC 184.108.40.206), alcohol dehydrogenase (ADH, EC 220.127.116.11), glutamate oxalacetate transaminase (GOT, EC 18.104.22.168), isocitrate dehydrogenase (IDH, EC 22.214.171.124), leucine aminopeptidase (LAP, EC 126.96.36.199), malate dehydrogenase (MDH, EC 188.8.131.52), phosphoglucose isomerase (PGI, EC 184.108.40.206), phosphoghtcomutase (PGM, EC 220.127.116.11), shikimate dehydrogenase (SKDH, EC 18.104.22.168), and triose phosphate isomerase (TPI, EC 22.214.171.124)] and five did not [acid phosphatase (ACPH, EC 126.96.36.199), diaphorase (DIA, EC 188.8.131.52), malic enzyme (ME, EC 184.108.40.206), 6-phosphogluconic dehydrogenase (6PGDH, EC 220.127.116.11), and superoxide dismutase (SOD, EC 18.104.22.168)]. Two cultivars, Campa and Campa Mejorada, had identical banding patterns for all enzymes tested. All others were identified as distinct cultivars because of isozyme differences. The identical isozyme profiles of `Campa' and `Campa Mejorada' probably indicate that they are the same cultivar. A cluster analysis of isozyme profiles showed that Spanish cultivars were clearly different from Californian cultivars.