Background and aims: Although osteoarthritis (OA) is managed mainly in primary care, general practitioners (GPs) are not always trained in its diagnosis, which leads to diagnostic delays, unnecessary resource utilization, and suboptimal patient outcomes. Methods: To address this situation, an International Rheumatologic Board (IRB) of 8 experts from 3 continents developed guidelines for the diagnosis of OA in primary care. The focus was three major topologies: hip, knee, and hand/finger OA. The IRB used American College of Rheumatology diagnostic criteria. Results: Care pathways based on clinical and radiological findings were developed to identify intervention thresholds for GPs/specialists. To optimize usefulness in the primary care setting, the guidelines were formatted as an uncomplicated, but comprehensive one-page decision tree for each topology, highlighting key aspects of the evaluation process and incorporating red flags. In a two-phase validation stage, the draft guidelines were evaluated by rheumatologists and GPs for project execution, content and perceived benefit. The strength of the guidelines lies in their user-friendly diagram and potential for broad application. Such guidelines will allow GPs to make an easy but definite diagnosis of OA and offer clear guidance about situations requiring an expert opinion. The guidelines have potential to improve patient outcomes and reduce the number of unnecessary procedures. Discussion and conclusions: This project demonstrated the feasibility of developing easy-to-use and effective visual decision trees to facilitate the diagnosis and management of OA of the hip, knee and hand/finger in primary care. The next step should be to conduct a large impact study of implementation of these recommendations in the diagnostic management of OA in general practice in different areas.