The distribution of electrophoretic variants in 8 red cell enzyme systems, representing 10 independent gene loci, has been examined in a large series of Marathi and Gujarati blood samples from Bombay. In the acid phosphatase system no PHsc genes were detected in Marathis and the frequency of PHsc in Gujaratis was only 0.004. The PHsB frequencies were 0.72 and 0.71 respectively. For 6-phosphogluconate dehydrogenase the PGDA frequencies were 0.97 and 0.98: a single case of the ‘Richmond’ variant was found in Gujaratis. The AK2 gene in the adenylate kinase system has a relatively high frequency, as in other Indian populations: the respective frequencies were 0.09 and 0.11. No variants were found at the PGM2 locus in the phosphoglucomutase system. For the PGMX locus PGM]1 frequencies were 0.65 and 0.69 for Marathis and Gujaratis. A single PGM 6–1 individual was found in the Marathis and a PGM 3–1 individual in the Gujaratis. No electrophoretic variant was found for the peptidase A, malate dehydrogenase or ‘oxidase’ systems. A single Pep B 2–1 person was found among the Marathis in the peptidase B system. Fourteen cases of the ‘Calcutta-1’ variant were found among 1,005 persons tested for lactate dehydrogenase. The LDH ‘Cal-1’ gene frequency was 0.0089 for Marathis and 0.005 for Gujaratis. The ‘Cal-1’ variant is widespread in India and has the highest world frequency for any LDH variant.