Psoriatic arthritis (PsA) is a chronic inflammatory joint disease which affects patients suffering from psoriasis. The genetic background especially the susceptibility loci on the short arm of the chromosome six contribute to PsA development. In our study, we looked for the role of the MICA and HLA-Cw genes polymorphisms in PsA pathogenesis. We investigated 100 PsA patients and 94 healthy Czech individuals. We found an association between HLA-Cw*06 and PsA namely PsA with psoriasis type I (age of psoriasis onset before 40 years) compared to healthy individuals (P (corrected) < 0.05, OR 2.56, CI 95% 1.33-4.76 and P (corrected) = 0.01, OR 3.03, CI 95% 1.53-5.88, respectively). The MICA-A9 allele of the transmembrane microsatelite MICA polymorphism occurred more frequently in PsA with psoriasis type II group (age of psoriasis onset after 40 years) than in controls, 58.6 versus 38.0%, respectively however, this finding did not reach a statistical significance after correction (P (corrected) = 0.085).