The long-term effectiveness of hysteroscopic treatment of menorrhagia and leiomyomas. One hundred fifty-six of 177 patients admitted to the St. Luke's/Roosevelt Hospital Center between November 1973 and November 1988 for hysteroscopic treatment of menorrhagia and/or uterine leiomyomas were followed for long-term complications and necessity for repeat surgery. Ninety-four patients underwent submucous resection alone and 62 patients underwent endometrial ablation with or without submucous resection. Among the submucous-resection group, 24.5% reported late postoperative problems and 15.9% underwent further surgery. After 9 years of followup, 83.9% of the patients had not required further surgery. Among the ablation group, 22.5% experienced recurrence of increased bleeding and 8.1% had another surgical procedure. After 6 years of follow-up, 91.3% of the patients had not required further surgery. Twenty-one patients became pregnant after submucous resection, with 18 infants delivered. No patients who underwent endometrial ablation became pregnant. This modality of treatment appears to be effective over the long term, although effectiveness appears to diminish with time. 