Among 1,106 patients with cervical disc disease in whom Cloward's operation had been performed over a fifteen-year period, 145 patients were reoperated upon with a new Cloward procedure. In the 1st year after the first operation 3/4 of the patients were operated upon on the previous level, whereas reoperations performed later mainly were done on new levels. The effect of the reoperation was poorer than the effect of the 1st operation. Early reoperations--which were due to: an initially unsatisfactory clinical course, postoperative complications or graft problems--had a poor result, but late reoperations--which were caused by relapses--showed a result corresponding to the first operation. The frequency of relapses leading to a 2nd Cloward operation was 8.8% in the first year falling to 0.2% in the following years of observation.