Of five patients in who sciatic paresis developed as the result of hemorrhage and hematoma following hip surgery, four were receiving prophylactic or therapeutic anticoagulants. The patient who was managed expectantly still had disabling motor and sensory deficity at follow-up. Three patients who had early operative decompression showed more complete return of nerve function. The fifth patient died three weeks after onset with the neuropathy still present. Severe low-back and buttock pain, ecchymosis over these regions, marked swelling in the thigh, sciatic-nerve tenderness, and a distal sciatic neural deficit in the ipsilateral lower limb of a patient who has had hip surgery are evidence of hemorrhage in the vicinity of the sciatic nerve. Early recognition and prompt surgical decompression can prevent irreversible nerve damage.