To measure the effects of a specialized postfall assessment intended to detect causes and underlying risk factors for falls, and to recommend preventive and therapeutic interventions. Randomized, controlled trial. A long-term residential care facility for elderly persons. Within 7 days of a fall, 160 ambulatory subjects (mean age, 87 years) were randomly assigned to receive either a comprehensive postfall assessment (intervention group, n = 79) or usual care (control group, n = 81). The postfall assessment included a detailed physical examination and environmental assessment by a nurse practitioner; laboratory tests; electrocardiogram; and 24-hour Holter monitoring. Probable cause or causes for the fall, identified risk factors, and therapeutic recommendations were given to the patient's primary physician. Through use of the assessment, many remediable problems (for example, weakness, environmental hazards, orthostatic hypotension, drug side effects, gait dysfunction) were detected. At the end of the 2-year follow-up period, the intervention group had 26% fewer hospitalizations (P less than 0.05) and a 52% reduction in hospital days (P less than 0.01) compared with controls. Patients in the intervention group had 9% fewer falls and 17% fewer deaths than controls by 2 years, but these trends were not statistically significant. Our study suggests that falls are a marker of underlying disorders easily identifiable by a careful postfall assessment, which in turn can reduce disability and costs.