The authors describe the clinical and radiological features, surgical procedures, and outcome of 18 cases of clivus meningiomas and six of apicopetroclivus meningiomas. There were 17 females and seven males, ranging in age from 26 to 69 years, with a mean age of 47 years. All except one showed cranial nerve deficits. Computed tomography accurately demonstrated tumor size and location. Cerebral angiography showed characteristic displacement of the basilar artery and its tributaries, with blood supply to the tumor largely via the meningohypophyseal trunk. Magnetic resonance imaging was excellent in delineating the relationship of the tumor to the brainstem and major vasculature. The surgical approaches used were transpetrosal-transtentorial (n = 9), combined transpetrosal-transtentorial-transzygomatic preauricular transpetrosal (n = 9), suboccipital-subtemporal (n = 2), suboccipital (n = 1), frontotemporal (first stage operation) followed by suboccipital (second stage operation) (n = 1), suboccipital-transpetrosal (n = 1), and orbitozygomatic-infratemporal preauricular transpetrosal (n = 1). Seventeen tumors were totally removed and seven subtotally. The operative mortality was 8% (two patients). Twenty patients developed new cranial nerve deficits within 1 month of surgery. The average follow-up period was 5 years, and the outcome was good or excellent in 12 cases. Transpetrosal approaches proved relatively safe and effective for radical tumor removal and, in two cases, permitted preservation of useful hearing.(ABSTRACT TRUNCATED AT 250 WORDS)