The frequency of occurrence of malignant neoplasms in the cases of pyoderma gangrenosum is not exactly determined, but it can be assessed to be at 7%. The aim of the study was to report a 26-year-old male patient with pyoderma gangrenosum coexisting with acute myelogenous leukaemia. The first skin lesions on both tibia occurred in June 2001. Prior to the proper diagnosis of pyoderma gangrenosum, the patient was treated surgically. Because of the dramatic dermatological and general condition in November 2001, the patient was admitted to the Dermatological Department of the Silesian Medical Academy in Katowice where the diagnosis of pyoderma gangrenosum was established. On the clinical and biochemical picture, the diagnosis of pyoderma gangrenosum within acute myelogenous leukaemia was made. Initially, cyclosporin A 200 mg orally per day in the therapy of pyoderma gangrenosum was administered to achieve a slight clinical improvement. Although chemotherapy leukaemia was performed, the patient died after 4 months of the confirmation of the acute myelogenous leukaemia diagnosis.