A comprehensive and systematic assessment of the current status of genetic association studies (GAS) for osteoarthritis was conducted. Data from 327 GAS involving 187 distinct genetic variants were analyzed and cataloged in CUMAGAS-OSTEO, a Web-based information system (http://biomath.med.uth.gr) that allows the retrieval and synthesis of data from GAS on osteoarthritis. In individual studies, 66 variants (mostly single nucleotide polymorphisms) showed significant associations with osteoarthritis risk. For 19 variants, the association was significant at P < 0.01, with an increased risk greater than 30%. Only 2.4% of studies had statistical power greater than 50% to detect a modest genetic effect. Nineteen variants were investigated by 4 or more studies, and their results were subjected to meta-analysis. Significant associations were derived for 2 variants (GDF5 rs143383, LRCH1 rs912428) in the main meta-analysis and for 2 other variants (TXNDC3 rs4720262, ESR1 rs2234693) in subgroup analysis by ethnicity or osteoarthritic body site. Heterogeneity ranged from none to high. In general, there was consistency of genetic effects across ethnic groups and body sites, and there was no differential magnitude of effect in large studies versus small studies. CUMAGAS-OSTEO may be a useful tool for identifying pertinent gene-osteoarthritis associations and providing an updated summary of risk effects.