Accurate diagnosis of vertebral osteoporotic fractures is crucial for the identification of individuals at high risk of future fractures. Different methods for radiological assessment of vertebral fractures exist, but a gold standard is lacking. The aim of our study was to estimate statistical measures of agreement and prevalence of osteoporotic vertebral fractures in the population-based Rotterdam Study, across two assessment methods. The quantitative morphometry assisted by SpineAnalyzer(R) (QM SA) method evaluates vertebral height loss that affects vertebral shape whereas the algorithm-based qualitative (ABQ) method judges endplate integrity and includes guidelines for the differentiation of vertebral fracture and nonfracture deformities. Cross-sectional radiographs were assessed for 7582 participants aged 45 to 95 years. With QM SA, the prevalence was 14.2% (95% CI, 13.4% to 15.0%), compared to 4.0% (95% CI, 3.6% to 4.5%) with ABQ. Inter-method agreement according to kappa (kappa) was 0.24. The highest agreement between methods was among females (kappa = 0.31), participants age >80 years (kappa = 0.40), and at the L1 level (kappa = 0.40). With ABQ, most fractures were found at the thoracolumbar junction (T12 -L1 ) followed by the T7 -T8 level, whereas with QM SA, most deformities were in the mid thoracic (T7 -T8 ) and lower thoracic spine (T11 -T12 ), with similar number of fractures in both peaks. Excluding mild QM SA deformities (grade 1 with QM) from the analysis increased, the agreement between the methods from kappa = 0.24 to 0.40, whereas reexamining mild deformities based on endplate depression increased agreement from kappa = 0.24 to 0.50 (p <0.001). Vertebral fracture prevalence differs significantly between QM SA and ABQ; reexamining QM mild deformities based on endplate depression would increase the agreement between methods. More widespread and consistent application of an optimal method may improve clinical care.