Anorexia nervosa (AN) is a serious psychosomatic syndrome, classified as an eating disorder. AN patients strive to lose weight below the normal limits defined for a specific age and height, achieving their goal even at the expense of extreme emaciation. AN has a multifactorial aetiology. Genetic factors are believed to be significant in the predisposition to the development of AN. In girls suffering from AN significantly lower levels of resistin (RES) in blood serum are observed as compared to healthy girls. These differences may lead to a thesis that functional genetic polymorphisms in RES coding genes can be responsible for this phenomenon. In our pilot study we demonstrated significant differences in the distribution of genotypes in the locus RETN c.-180C>G of the RES gene in 67 girls with AN and 38 healthy girls. It seems reasonable to compare the frequency of polymorphisms of RETN c.62G>A and RETN c.-180C>G in the RES gene in girls with AN and in healthy subjects in a bigger cohort and to analyse correlations between individual variants of the polymorphisms referred to above and the RES levels in blood plasma.