Psoriasis vulgaris is a HLA-associated common and persistent inflammatory skin disease of unknown aetiology. The transporters associated with antigen processing (TAP) genes are polymorphic genes located in the HLA class II region and due to their essential involvement in class I antigen presentation might be additional susceptibility genes to psoriasis. To investigate the possible involvement of the TAP1 gene in the pathogenesis of psoriasis, we analysed its polymorphism in 169 Polish patients with psoriasis vulgaris and compared them with 66 healthy controls. The frequency of TAP1*D was significantly increased in the patients, compared to the control group. The TAP alleles were also analysed with respect to the age of onset of psoriasis in the patients but no significant differences were recorded. In conclusion, our data suggest that the TAP1*D allele could lead to genetic susceptibility to psoriasis vulgaris in Poles.