Idiopathic thrombocytopenic purpura (ITP) is a relatively common hematologic disorder. Steroids and splenectomy constitute the main modalities of treatment. Although the indications for these therapies are well established in the literature, the timing of splenectomy remains controversial. This report retrospectively reviews 712 consecutive patients with ITP hospitalised in 9 medical centers in Israel between the years 1977 and 1987. The clinical presentations, the time required for a response to steroids and the remission rate following splenectomy were all similar in children with ITP who were hospitalised and adults. There were however marked differences in associated conditions, predominantly viral infections in children, and autoimmune disorders, neoplaia or infections in adults. The overall response to initial steroid therapy was 82% in children and 74% in adults. Ninety-three percent of those responding did so within 60 days of starting treatment. One hundred and seventy-three patients underwent splenectomy; 123 (71%) achieved a prolonged complete remission. We recommend early splenectomy in patients not responding rapidly to corticosteroid treatment. This study demonstrates that chronic, more severe ITP in children requiring hospitalisation has a marked similarity to the disease in adults. Many children, however, present with mild transient thrombocytopenia that does not necessitate hospitalisation or a specific therapy.