To examine the distribution of different polymorphisms in genes of the 5-HT system in patients with anorexia nervosa (AN) and bulimia nervosa (BN), we analyzed the distribution of a polymorphism (-1438G/A) and the presence of known mutations in 5-HT2A and 5-HT2C receptor genes in 168 Italian female patients affected by AN and BN. Patients with AN restricting type (ANr) only, unlike those with AN binge eating/purging type (ANp) and BN purging type (BNp), showed a statistically significant difference in 5-HT2A-1438A/A genotype frequency with respect to controls. With regard to the other polymorphisms, no differences were found in the studied groups with respect to controls. 5-HT2A promoter polymorphism is probably implicated in the susceptibility to eating disorders and its involvement is more significant in ANr, when compared with ANp and BNp.