Abstract Objective To investigate whether methotrexate (MTX) use is associated with bone mineral density (BMD) in patients with polymyalgia rheumatica (PMR) and various forms of vasculitis. Methods Rh-GIOP is a cohort study designed to evaluate bone health in patients with inflammatory rheumatic diseases. This cross-sectional analysis assessed the baseline visits of all patients with PMR or any kind of vasculitis. Following univariable analysis, multivariable linear regression analysis was performed. The lowest T-score of either the lumbar spine or the femur was chosen as the dependent variable to examine the relationship between MTX use and BMD. These analyses were adjusted for a variety of potential confounders, including age, sex, and glucocorticoid (GC) intake. Results Of 198 patients with PMR or vasculitis, 10 patients were excluded for very high GC dose (n = 6) or short disease duration (n = 4). The remaining 188 patients had the following diseases: PMR 37.2%, giant cell arteritis 25.0%, granulomatosis with polyangiitis 16.5%, followed by rarer diseases. The mean age was 68.0 ± 11.1 years, mean disease duration was 5.58 ± 6.39 years, and 19.7% had osteoporosis by dual x-ray absorptiometry (T-score ≤ −2.5). 23.4% were taking MTX at baseline with a mean dose of 13.2 mg/week (median: 15 mg/week). 38.6% of those used a subcutaneous preparation. MTX users had similar BMD compared to non-users (minimum T-scores −1.70 (± 0.86) versus −1.75 (± 0.91), respectively; p = 0.75). There was no statistically significant dose–response relationship: neither current nor cumulative dose were associated with BMD in unadjusted or adjusted models (current dose: slope −0.02; −0.14 to 0.09; p = 0.69; cumulative dose: slope −0.12; −0.28 to 0.05; p = 0.15). Conclusion In the Rh-GIOP cohort, MTX is used in about a quarter of patients with PMR or vasculitis. It is not associated with BMD levels.