Abstract: Pattern of Rheumatic Diseases in Iran: They have the same frequency and the same pattern as in Western countries. A study from 1993 demonstrated a prevalence of 32.6% among adults (31.4% in the USA, Cunningham 1984). Inflammatory disorders counted for 11% of all rheumatic diseases. The ratio of RA to AS was 8/1 (7/1 in USA), and SLE to Scleroderma 3.5/1 (3.6/1 in USA). Psoriatic arthritis and Reiter's syndrome were ...