Previous reports showed associations between psoriasis and chronic diseases. Little is known about the association between osteoporosis and psoriasis. The goal of the study was to assess the association between psoriasis and osteoporosis in a population-based case-control study, utilizing the database of a large health-care provider organization in Israel, Clalit Health Services. Patients (aged 51-90 years) diagnosed with psoriasis were compared with a sample of age- and sex-matched enrollees without psoriasis regarding the prevalence of osteoporosis. Data on health-related lifestyles and other comorbidities were collected. The study included 7,936 psoriasis cases and 14,835 controls. The prevalence of osteoporosis was significantly greater in males with psoriasis compared with the control group (3.1 vs 1.7%, P0.001, odds ratio (OR)1.86, 95% confidence interval (CI): 1.44-2.39) and slightly greater in females with psoriasis (22.3 vs 20.2%, P0.008, OR1.13, 95% CI: 1.03-1.25). A multivariate logistic regression model demonstrated that after controlling for confounders, psoriasis was significantly associated with osteoporosis in males (adjusted OR1.70, 95% CI: 1.31-2.19, P0.001). The weak association between psoriasis and osteoporosis in females lost statistical significance in a multivariate model (adjusted OR1.09, 95% CI: 0.98-1.21, P0.100). Psoriasis was found to be associated with osteoporosis among males, but not among females.