OBJECTIVES: To provide a systematic review of current literature on the association of obesity and outcome of rheumatic diseases. METHODS: We conducted a literature search using PubMed^®, Embase^® and PsycInfo^® and related keywords. We categorized the articles into three categories, namely positive, neutral or negative association of obesity and outcomes of rheumatic diseases. The subject population, country, type of studies, number of patients, measurement of obesity and outcomes assessed were presented. RESULTS: A total of 3454 articles were screened and 47 articles were found to be relevant to the objective. 28 studies (59.6%) with 40001 subjects showed that obesity has a negative association with outcomes of rheumatic disease. 11 studies (23.4%) with 3857 subjects showed that obesity has a positive association with outcomes of rheumatic diseases. 8 studies (17.0%) with 1767 patients showed that obesity has a neutral association with the outcomes of rheumatic diseases. The disease population of most of the studies found by this systematic review are subjects diagnosed with rheumatoid arthritis (RA). Most of the studies were completed in western populations such as America. CONCLUSIONS: A systematic review on the association of obesity and outcome of rheumatic diseases was conducted. Most of the studies are based on Western populations and most of the studies showed that obesity is negatively associated with outcome of rheumatic diseases. Further studies devoted to examining subjects from other regions, such as Asia and Africa, whom are suffering from various types of rheumatic diseases, in particular those other than RA are warranted.