INTRODUCTION AND METHODS: Ten currently available classifications were tested for their ability to describe a continuous cohort of 300 adult patients affected by bone and joint infections. Each classification only focused, on the average, on 1.3 ± 0.4 features of a single clinical condition (osteomyelitis, implant-related infections, or septic arthritis), being able to classify 34.8 ± 24.7% of the patients, while a comprehensive classification system could describe all the patients considered in the study. RESULT AND CONCLUSION: A comprehensive classification system permits more accurate classification of bone and joint infections in adults than any single classification available and may serve for didactic, scientific, and clinical purposes.