The authors have reviewed the pattern of drainage of Hemovac devices in 107 arthroplasties of the hip. Drainage ceased in 55 hips (51%) within 18 hours and 93 hips (89%) within 24 hours. The mean drainage volume was 303 cc in femoral head replacement, 498 cc in simple total hip replacement, and 663 cc in extensive total hip replacement. Ninety nine per cent of the total drainage had been achieved within 24 hours, indicating that drainage devices can be removed then rather than between 24 and 72 hours as had been previously recommended. This early removal will help reduce the possibility of retrograde infection, and promote more comfortable rehabilitation after operation.