Knee injuries continue to be an increasingly common and highly visible problem presenting to the sports medicine physician. The physicians who handle knee injuries will be challenged by patients, coaches, trainers, business agents, the press, and family members with an ever-increasing sophistication of medical knowledge. An understanding of the underlying structure and function of the commonly injured ligaments, menisci, and the patellofemoral joint is discussed. Diagnosis by physical examination is encouraged. Conservative and surgical treatment options are reviewed as are the considerations involved in deciding the time to return to sports.