Twenty-four patients were evaluated and diagnosed, between August 1975 and July 1989, as having probable osteoid-osteoma. Fifteen patients had operative treatment (twelve immediate and three delayed); all fifteen had complete relief of pain. The remaining nine patients were treated with non-steroidal anti-inflammatory medications; all nine had complete relief of pain, and six had resolution of the symptoms without using non-steroidal anti-inflammatory drugs, after an average of thirty-three months (range, thirty to forty months) of treatment. Thus, long-term administration of non-steroidal anti-inflammatory drugs can often be as effective as excision for the treatment of osteoid-osteoma, without the morbidity that is associated with the operation, especially in patients in whom operative treatment would be complex or might lead to disability.