Objective: To evaluate the epidemiological features and risk factors for crystal induced arthritis in patients presented to Rheumatology Clinic, Sohag University, Upper Egypt. Patients and Methods: A hospital based study was carried on 30 patients; 17 male and 13 female attending the outpatient Clinic of Rheumatology and Rehabilitation Department of Sohag University Hospital in the period from April 2011 to December 2011 complaining of lower limb effusion. All patients aged 40 years or above with a mean age of 47.5 years. The mean duration of arthritis was 5.7 months. Each patient was subjected to complete history taking, clinical examination, computed tomography (C.T), ultrasonography (U.S.) and synovial fluid examination by polarizing microscopy. Saline were injected and aspirated to withdraw crystals in 3 (12.5 %) patients who have minimal effusion. Results: Crystal induced arthritis was diagnosed in 80% of patients by any of the three means collectively. All crystal induced arthritis patients were crystal positive by polarizing microscope, 83.3 % of them were crystal positive by U.S., while C.T. was not able to visualize crystals directly. C.T. was very sensitive in detecting erosions, cysts, joint space narrowing and calcification associated with crystals. Shorter duration of arthritis was usually associated with Monodosium Urate (MSU) and Calcium Pyrophosphate Deposition (CPPD) crystals and longer duration was usually associated with Basic Calcium Phosphate (BCP) crystals. Most of the participant with MSU crystals had monoarthritis, and most of those with BCP and CPPD crystals had oligoarhtritis. Male to female ratio was 14:10 (1.4); 9 (70 %) of the female participants were postmenopausal, while 4 (30 %) were premenopausal. Eight (26.7%) of the participants with crystal induced arthritis were cigarette smokers and all of them had MSU (6) or CPPD (2) crystals. All of the participants have osteoarthritis. Seven of those patients with crystals had hypertension and most of them had BCP crystals, four followed by MSU three followed by finally CPPD two. The seven patients with diabetes had MSU crystals and to a lesser extent CPPD and BCP. Two of the four patients using diuretics had MSU crystals and the other 2 had BCP. Ten patients (41.6 %) received injection or aspiration at the same joint before, the great majority of them has MSU crystals. Ten patients have a body mass index above 25 and most of them (eight) were associated with MSU crystals. 33.3% of the patients with crystal arthropathy have a history of chronic use of NSAIDS, 75% of them have MSU crystals. Conclusions: Crystal induced arthritis is an undiagnosed not rare arthritis in Upper Egypt usually associated with osteoarthritis, old age, obesity, chronic drug intake especially NSAIDS. Most of these risk factors could be modified by dissemination of knowledge about disease clinical features and methods of diagnosis and risk factor could improve the outcome for those patients