Introduction. The etiology of rheumatic diseases is not absolutely clear and a lot of genetic and environmental factors are considered to be involved. The triggering factors for the development of rheumatoid diseases are considered to be: genetic predisposition, injuries of the musculoskeletal system, different pathogens, metabolic diseases, bad habits, etc. Aim of the study. In this work, “The Role of Infections in the Development of Rheumatic Diseases,” a case-control study investigated the presence of infection in a particular category of rheumatic diseases. Materials and methods. Thus, of the 500 studied cases, the infection was present in 347 cases, which is 69.4%. The data for the statistical study were taken from the patient history of the rheumatology department for January-October 2017. Results. The distribution among the studied cases is the next one: ankylosing spondylitis - 59 cases (11.8%), the presence of infection in 29 cases (8.35%), reactive arthritis - 70 cases (14%), the presence of infection - 57 (16.45%), seronegative undifferentiated arthritis - 46 cases (9.2%) with signs of infection (6.9%), psoriatic arthritis 118 cases (23.6%) with infection - 98 cases (28.2%), rheumatoid arthritis 137 (27, 4%) the presence of infection in 101 (29.2%) cases, systemic lupus erythematosus 18 cases (3.6%), the presence of infection in 13 cases (3.74%), gout 17 cases (3.4%), with infection 9 cases (2.59%), undifferentiated connective tissue diseases 6 counts (2.6%) with infection 4 cases (1.2%), scleroderma 13 cases (2.6%) with infection 7 cases (2%), Vasculitis 10 cases (2%) of which 5 cases (1.45 %) with infection. The most common signs of the disease are rheumatoid factors - in 123 cases 35.4%, CRH-150 cases (43.2%), ASLO-88 cases (25.3%), Anti Hb core sum-83 cases (23.9 %), frequent tonsillitis in the anamnesis of 69 cases (19.8%), pharyngeal smear of 49 cases (14.1%), genitourinary infection of 48 cases (13.9%). Conclusions. Based on the obtained results we can confirm the presence of infection is two thirds of the total cases.