BACKGROUND Obesity is a debilitating growing condition and represents a challenge for every surgeon. It is associated with the activation of the inflammatory pathway and this may have a negative impact on the natural history of some rheumatic diseases. Bariatric surgery, reducing obesity, could bring to a minor activation of the well-known inflammatory pathway with improvement of these diseases. The aim of this review is to investigate the role of weight loss, achieved through bariatric surgery, in rheumatic diseases. METHODS A systematic review of literature was undertaken to evaluate weight loss subsequent to bariatric surgery in obese patients suffering from some rheumatic diseases (Rheumatoid Arthritis, Psoriasis, Psoriatic Arthritis, Fibromyalgia, Osteoarthritis, Systemic Lupus Erythematous). Three major databases (PUBMED, EMBASE and WEB OF SCIENCE) were searched. RESULTS Three-hundred studies were identified. After screening of titles, abstracts and inclusion criteria sixteen articles were included. Of the selected articles, seven were reviews, five were case reports, one was a clinical report, one was a retrospective study, one was a cohort study and one was an author manuscript. CONCLUSIONS Weight loss, obtained through bariatric surgery, seems to reduce serum inflammatory markers as a consequence of the inflammatory pathway reduction and this is connected with both the improvement of some rheumatic diseases as well as with the reduction in the use of medicaments (steroids and immunosuppressors).