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Objective Existing gout classification criteria have suboptimal sensitivity and/or specificity, and were developed at a time when advanced imaging was not available. The current effort was undertaken to develop new classification criteria for gout. Methods An international group of investigators, supported by the American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) conducted the following studies: a systematic literature review of advanced imaging, a diagnostic study in which monosodium urate (MSU) crystals in synovial fluid or tophus was the gold standard, a ranking exercise of paper patient cases, and a multi-criterion decision analysis exercise. These data formed the basis for developing the classification criteria, which were tested in an independent dataset. Results The entry criterion for the new classification criteria requires at least one episode of peripheral joint or bursal swelling, pain, or tenderness. The presence of MSU crystals in a symptomatic joint/bursa (i.e., synovial fluid) or in a tophus is a sufficient criterion for gout classification, and does not require further scoring. The domains of the new classification criteria include clinical (pattern of joint/bursa involvement, characteristics and time-course of symptomatic episodes), laboratory (serum urate, MSU-negative synovial fluid aspirate), and imaging (double-contour sign on ultrasound or urate on DECT, radiographic gout-related erosion). The sensitivity and specificity of the criteria are high: 92% and 89%, respectively. Conclusions The new classification criteria, developed using a data-driven and decision-analytic approach, have excellent performance characteristics and have incorporated current state-of-the-art evidence regarding gout.