For patients with adult chronic immune thrombocytopenia (ITP) splenectomy (SE) is a highly effective treatment, but there are still uncertainties regarding the long-term efficacy and safety. We evaluated the long-term efficacy and safety of SE in 48 consecutive adult patients with chronic ITP (26 women, 22 men) who underwent SE between 1990 and 2001 at the General Hospital in Vienna, Austria. All patients had no remission after steroid treatment and were steroid dependent. The median age at the time of SE was 44 years (range: 16-77 years). Of 48 patients, 37 achieved a complete remission (CR, platelet count >100 x 10(9)/l), 8 a partial remission (PR) (platelet count 30-100 x 10(9)/l), and 2 had no response (NR). The probability of the overall survival was 98% at a median postsplenectomy observation time of 3.5 years. Seven patients with CR and four patients with PR relapsed. There were no relapses after 1 year. The probability of continuous complete remission (CCR) at 10 years was 79%. The probability of having a platelet count of >100 x 10(9)/l or >30 x 10(9)/l was 61% and 67%, respectively, at 5 and 10 years after splenectomy. Of the 11 relapsed patients, 5 had a second CR ( n=3) or PR ( n=2). The postoperative platelet count was the best predictor for a long-term remission. All patients with postoperative platelet counts >250 x 10(9)/l remained in CR. Patients aged >45 years had a similar success rate as compared with younger patients. Three patients had infections (one pneumonia and two fever of unknown origin) requiring hospitalization, but none had overwhelming septicemia.