A 61 years-old male patient suffering from psoriatic arthritis for over 12 years was treated with Etanercept 25 mg subcutaneously twice a week. From the second month of therapy, we observed a decrease of platelet count that achieved the minimal value at the third month of therapy (95 x 103/μl). Being the thrombocytopenia slight and asymptomatic we decided to continue the treatment After the third month of therapy the platelet count gradually increased until the forth month, when the number of platelets recovered the initial value. When we restart the therapy with etanercept,After two months of therapy PASI was 6,4, Ritchie index 3 and a decrease of platelet count was noted achieving the minimal value at the third month of treatment(94,4 x 103/μl).