From 1976 to 1977 308 patients were treated with multiple aorto-coronary vein-bypass. Fiftytwo patients receiving sequential bypasses were compared with 256 patients in whom conventional multiple anastomoses were performed. The rate of postoperative bypass failure did not differ significantly in the two types of anastomoses: 16 per cent in sequential as compared to 18 per cent in conventional bypass. In both cases the circumflex-system was afflicted by bypass failure more frequently (20 per cent each). The practical and theoretical advantages and disadvantages of the two procedures are discussed. Sequential aortocoronary vein-bypass is considered the method of choice for certain combinations of coronary stenoses and also if an adequate length of vein can not be obtained.