The long-term effect of sacral rhizotomy in 24 patients with coccygodynia was evaluated. Prior to section of both the S-4 and S-5 roots all patients had coccygeal pain and tenderness which had not responded to severe conservative and surgical therapeutic measures. In 8 patients the coccalgia (S-4 S-5 pain) was associated with unilateral pain in the S-3 area, in another 8 patients it was associated with disabling lumbago and in the remaining group of 8 patients coccalgia occurred without pain in neighbouring areas. Only 6 patients responded well to sacral rhizotomy. All these patients belonged to the final group of 8 patients with pain distribution limited to the S-4 S-5 area. Serious complications occurred after 6 of the 24 rhizotomies. Five of these patients belonged to the two groups who besides coccalgia also had disabling lumbago or signs of rhizopathy about the S-4 level. A restrictive attitude to sacral rhizotomy in coccalgia is recommended especially when it is associated with pain in neighbouring areas and also if there is any reason to believe that there are factors present predisposing to the development of arachnoiditis.