Twenty-one patients with nonresectable refractory meningiomas were registered on a study giving tamoxifen 40 mg per M2 b.i.d. for four days, then 10 mg b.i.d. thereafter. Nineteen were eligible and evaluated for response. One patient (5%) achieved an MRI-documented partial response while two had a minor response measured on CT scan which was of short duration (4 and 20 months). Six patients (32%) remained stable for a median duration of 31 + months while ten (53%) demonstrated progression. Twenty-two percent (22%) reported subjective improvement though this did not correlate with objective improvement in all cases. At present, a definite recommendation for the use of tamoxifen in refractory meningiomas cannot be made. Further evaluation of hormonal therapy of meningiomas with a consensus for definition of endpoints for evaluation of response in view of the difficulty of evaluating radiologic findings with clinical outcome, is needed.