The nine-year experience with sixty patients who had had a giant-cell tumor of a long bone was reviewed to determine the rate of recurrence after treatment with curettage and packing with polymethylmethacrylate cement. The demographic characteristics, including the age and sex of the patient and the site of the tumor, were similar to those that have been reported for other large series. An average of four years (range, two to ten years) after the operation, the over-all rate of initial local recurrence was 25 per cent (fifteen of sixty patients). Patients who had had a tumor of the distal aspect of the radius had a higher rate of recurrence (five of ten) than those who had had a tumor of the proximal aspect of the tibia (seven [28 per cent] of twenty-five) or of the distal part of the femur (three [13 per cent] of twenty-three). Higher rates of recurrence were also noted for patients who had had a pathological fracture (three of six), those who had had a Stage-III tumor according to the classification of Campanacci et al. (six of sixteen), and those who had not had adjuvant treatment with either a high-speed burr or phenol (eight of nineteen). Patients who had had an initial recurrence after packing with cement had a low rate of secondary recurrence when the initial recurrence had been treated with a wide resection or a second intralesional procedure (zero of ten and one of five patients, respectively), after an average of three years (range, ten months to eight years). No patient had a multicentric tumor or metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)