Bleeding times were performed on 71 hemophiliacs using the Simplate II device. Eight patients receiving Indocin or Motrin for hemophilic arthropathy were evaluated separately from the remaining 63 who had a mean bleeding time of 7.65 +/- 3.20 min (1 SD) compared to the control group of 5.35 +/- 1.49 min (p less than 0.005). No difference was found when 26 mild hemophiliacs who had received less than 10,000 U of clotting factor concentrate the previous year and no infusions in at least 3 mo were compared with 28 severe hemophiliacs who had received greater than 20,000 U of clotting factor concentrate the previous year and had been infused within 1 mo of testing. Ten patients (16%) had bleeding times greater than 10 min. Bleeding times remained prolonged on repeat evaluations in 7 of these patients, 3 of whom had mild disease and all of whom had normal platelet aggregations in response to arachidonic acid. We conclude that the bleeding time is longer than normal in hemophilia. This abnormality is not related to disease severity, recent transfusions, or the use of nonsteroidal antiinflammatory drugs.