Rheumatoid arthritis is a chronic autoimmune disease of the joints of unknown etiopathogenesis. It affects between ~0.5 and 1% of the total population and occurs 2–3 times more often in women than in men. Several antibodies have been identified in the serum of patients with RA, including rheumatoid factors (RF), anti-citrullinated protein antibodies (ACPA) and anti-carbamylated protein antibodies. These autoantibodies can form immune complexes in the joints, leading to inflammation and damage to the articular cartilage. A characteristic symptom of advanced RA is persistent inflammation of the synovium, which usually affects peripheral joints in a symmetrical way. The exact aetiology of RA is unclear,it is known to be a multifactor disease in which a complex interplay between the host and the environment determines the overall risk of being susceptible to the disease, as well as its persistence and severity. Below we present the RA risk factors including main individual risk factors as hormonal factors, hereditery factors, epigenetic factors as well as the risk of concomitant environmental factors of RA as diet, cigarettes and alcohol abuse. Environmental contaminants, socio-economic factors and molecular mechanisms of RA known so far.