Sixty-one patients were followed for an average of thirty months (range, twenty-four to thirty-five months) after arthrodesis of the lumbar or lumbosacral spine with pedicle screw-plate fixation for painful degenerative arthritis, spondylolisthesis, or pseudarthrosis. The patients rated the clinical result according to an analog scale. Most patients reported a marked decrease in pain and an increase in function, and two-thirds were able to work full time. The result of the operation was regarded as a clinical failure if the patient considered it so, if an additional operation had been done, or if the functional and pain scores were not good (that is, if the patient was not able to work full time and the rating for pain was more than 5 of 10 points). Seventeen (28 per cent) of the patients were considered to have a clinical failure, with the lowest rate (20 per cent) for patients who had painful degenerative arthritis and the highest rate (47 per cent) for patients who had had a pseudarthrosis before the operation. The rate of fusion was 90 per cent in patients who had painful degenerative disease, 93 per cent in patients who had spondylolisthesis, and 65 per cent in patients who had had a pseudarthrosis preoperatively.