The performance characteristics of hyaline articular cartilage measurement on MRI need to be accurately delineated prior to widespread application of this technology. Our objective was to assess the rate of natural disease progression of cartilage morphometry measures from baseline to one year in knees with OA from a subset of participants from the OAI. Subjects included for this exploratory analysis are a subset of the approximately 4700 participants in the OAI Study. Bilateral radiographs and 3T MRI (Siemans Trio) of the knees and clinical data are obtained at baseline and annually in all participants.160 subjects from the OAI Progression subcohort all of whom had both frequent symptoms and, in the same knee, radiographic OA (ROA) based on a screening reading done at the OAI clinics were eligible for this exploratory analysis. One knee from each subject was selected for analysis. 150 participants were included. Using sagittal 3D DESSwe MR images from the baseline and 12 follow-up month visit, a segmentation algorithm was applied to the cartilage plates of the index knee to compute the cartilage volume, normalized cartilage volume (Volume normalized to bone surface interface area), and percent denuded area (Total Cartilage Bone Interface area denuded of cartilage). Summary statistics of the changes (absolute and percentage) from baseline at one year and the standardized response mean (SRM), i.e. mean change divided by the standard deviation change were calculated. On average the subjects were 60.9 years of age and obese with a mean BMI of 30.3 kg/m2. The SRMs for cartilage volume of various locations are central medial tibia -0.096, central medial femur -0.394 and patella -0.198. The SRMs for normalized cartilage volume of the various locations are central medial tibia -0.044, central medial femur -0.338 and patella -0.193. The majority of participants had denuded area at baseline in the central medial femur (62%) and central medial tibia (60%). In general the SRMs were small. These descriptive results of cartilage morphometry and its change at the one year timepoint from the first substantive MRI data release from the OAI Progression subcohort indicate that the annualized rates of change are small with the central medial femur showing the greatest consistent change.