Two hundred twenty-eight patients with acoustic neuromas were seen between 1974 and 1985. Twenty-eight received no surgical treatment. Five patients who had undergone previous partial excision were excluded. The mean age was 71 years. The mean expected survival was 14.3 years. The mean follow-up interval was 51 months (range 12 to 120 months). All patients underwent at least two CAT scans (mean = 4). Tumor size ranged from 4 mm to 30 mm. Three patients underwent insertion of ventricular-peritoneal shunt for hydrocephalus (mean 16 months after presentation) and two patients partial tumor removal (mean 30 months after presentation). Tumor growth was measured in each patient using CAT scanning. Monitoring by clinical examination and regular CAT scanning is possible, but in this study 20% of patients required surgical treatment within one third of their expected survival time. This suggests that an expectant attitude for this group of patients may be a debatable form of management.