Stress discography is that done during the time in which the subject's pain is present at a significant level of intensity. This prospective study examines the findings in 200 patients who were evaluated for low-back pain. A standardized injection technique was used and the contrast pattern within the disc was studied radiographically and with CT scanning. Pain response was recorded. Familiar low-back pain was reproduced in all cases, and familiar leg pain in 46% of cases. Of 549 discs studied, 319 reproduced familiar pain, an average of 1.6 discs per patient. Pain reproduction occurred in 69% of the L5 discs, 62% of the L4 discs, and 25% of the L3 discs. Internal disc disruption was present in 302 discs, but extruded annular material was found in only 19. Stress discography is a useful diagnostic study in evaluating patients with low-back pain.