This study was designed to reveal the variety and contribution of different rheumatic diseases in a non-referral rheumatology outpatient clinic. In this retrospective cross-sectional study, the data in medical records of all patients visited for the first time in the rheumatology clinic of a general hospital from the beginning of April 2016 to the end of March 2017 was gathered and evaluated for demographic characteristics, complaints, and diagnoses. A total of 2063 medical records were assessed. Among them, 2006 individuals were diagnosed with a rheumatologic disease. The mean age of patients was 48.72 ± 15.51, and females constituted 74.88% of patients. The distribution of diseases was as follows: 345 (17.20%) inflammatory, 1594 (79.46%) noninflammatory, and 67 (3.34%) both groups. The most common diagnosis was knee osteoarthritis (29.42%). Frequency distribution of other common diagnoses was in the following order: periarticular disease (15.53%), nonspecific generalized pain (8.75%), lumbar discopathy (6.24%), and rheumatoid arthritis (6.20%). The most frequent complaints were knee pain (30.96%), back pain (10.18%), and hand pain (9.35%). Among periarticular diseases, plantar fasciitis (17.27%), carpal tunnel syndrome (16.36%), and rotator cuff tendinitis (12.05%) were the most frequent disorders. More than half of the diseases included degenerative joint diseases, periarticular diseases, nonspecific musculoskeletal pain, and low back pain. The most prevalent diseases should be prioritized in the curriculum of medical education for undergraduate students. Proper policies for patient education, public health programs, and modified lifestyle may reduce morbidity among patients and costs forced upon healthcare providers and governments.