Radiographs and bone scans of 40 young athletes with low back pain were reviewed retrospectively to correlate the imaging findings and assess the value of scintigraphy in the diagnosis of these patients. The radiographs were positive for spondylolysis with or without spondylolisthesis in 15 (38%), and scintigraphy showed focal disease in the posterior vertebral elements in 14 (35%). Five patients had positive radiographic studies but normal scans, indicating old injuries; four patients had positive scintigrams but normal radiographs, suggesting early or active injuries. The authors use radiography as the initial examination in the evaluation of patients with low back pain. Scintigraphy is most useful in early stages, when radiographs may be normal; and in cases in which the age and activity of a radiologic abnormality cannot otherwise be accurately determined before therapy.