The polymorphism of the human red cell phosphoglucomutase 1 (PGM1) in samples from Egyptians (n = 134) was investigated using isoelectric focusing in thin-layer polyacrylamide gel. In the studied population samples nine common phenotypes were observed, and the calculated frequencies for the genes PGM1+1, PGM1-1, PGM2+1 and PGM2-1 were 0.6381, 0.0821, 0.2201 and 0.0597, respectively. The observed and expected phenotypes provide a good fit to Hardy-Weinberg equilibrium. The four alleles system will increase the probability of excluding a man falsely accused of paternity to 30% as compared with 16% if the two alleles system is used.