Current treatments for osteoarthritis are pain relief and total joint arthroplasty. There is a clinical need for early osteoarthritis diagnostic methods for potential preventive interventions. The resolution achieved with radiography, magnetic resonance imaging (MRI), and arthroscopy is too limited for the assessment of early disease. The high resolution, small fiber-optic probes, and real-time imaging of optical coherence tomography (OCT) makes this method ideal for assessing articular cartilage. In this article, we describe in vivo human arthroscopic OCT with qualitative baseline comparisons made with MRI and arthroscopy. Two-year MRI follow-ups are under way to quantitatively compare OCT with MRI and to assess the long-term outcomes of changes noted in the OCT images.