A study was conducted to investigate the variability of interpretation of plain lumbar spine radiographs by rheumatologists in benign low-back pain (LBP). Intra- and interobserver agreement in classifying the presence of primary radiologic abnormalities according to preestablished criteria was assessed by the Kappa statistic in 115 anteroposterior and lateral radiograms. A significant variability of interpretation was observed for many findings often considered important in benign LBP, Particularly, low levels of agreement were observed for apophyseal joint abnormalities, Schmorl's nodes, spondylolysis, and structural deviations. Elaboration and validation of better standardized criteria for the main radiologic abnormalities is needed to improve the reliability of interpretation of lumbar spine radiographs.