Thirteen members of a family of 182 demonstrated laboratory or historical evidence of thrombocytopenia. The onset of bleeding symptoms occurred around the age of 6 years, followed by spontaneous remission of symptoms but not thrombocytopenia in early adult life. Treatment ranged from symptomatic care to long-term steroid therapy or splenectomy. The disorder is inherited in an X-linked recessive manner but appears to be distinct from the Wiskott-Aldrich syndrome in other respects.