The purpose of this study is to determine the diagnostic properties of the clinical gout diagnosis (CGD) proposal in patients with gout and other rheumatic diseases. We investigated the presence of current or past history of the previously published CGD criteria: (1) >1 attack of acute arthritis, (2) mono/oligoarthritis attacks, (3) rapid progression of pain and swelling (<24 h), (4) podagra, (5) erythema, (6) unilateral tarsitis, (7) probable tophi, and (8) hyperuricemia. CGD was established in patients with greater than or equal to four out of eight of these criteria. Demographic data and comorbidities were also considered. Statistical analysis included diagnostic test evaluation (sensitivity, specificity, likelihood ratios, positive predictive values and receiving operating characteristic curves). One hundred and sixty-seven patients with the following diagnoses were included: gout (most in intercritical period, n = 75), rheumatoid arthritis (RA, n = 30), osteoarthritis (OA, n = 31) and spondyloarthritis (SpA, n = 31). All gout patients had MSU crystal demonstration and constituted the gold standard for diagnostic test evaluation. There were significant differences across diagnostic groups in most demographic variables and comorbidity. The presence of greater than or equal to four out of eight of the CGD criteria were found in 97% patients with gout, in two patients with SpA, and one each with RA and OA. The sensitivity, specificity, and LR+ of greater than or equal to four out of eight of the CGD criteria were 97.3%, 95.6%, and 22.14, respectively. The presence of more than or equal to four out of eight items from the CGD proposal is highly suggestive of gout.