Based on the hitherto published population data of the human red cell PGM1 and acid phosphatase polymorphisms, the geographical distributions of their gene frequencies were analyzed. As far as the acid phosphatase alleles are concerned, a marked geographical gradient was found as the Pa and Pb alleles showed significant correlations with the mean annual temperatures of the various human biotopes (Pa:r = –0.706; Pb:r = +0.812). Against that, the world distribution of the PGM1 alleles did not show a comparable correlation (PGM11:r = +0.063; PGM21:r = –0.063). The possible reasons for the distribution pattern of the acid phosphatase alleles are discus