The goal of this study was to compare MR imaging with arthroscopy in evaluating triangular fibrocartilage (TFC) pathology. The results of 178 MR imaging examinations of the wrist were independently reviewed by two musculoskeletal radiologists who were unaware of the the clinical history, including any subsequent surgery. One hundred forty-nine of these studies were obtained from symptomatic patients. Of these patients, 56 underwent arthroscopic evaluation of the TFC. The remaining 29 studies were obtained from control volunteers and duplicate cases to reduce bias. The data were divided into categories based on Palmer's classification of TFC injury. Diagnostic sensitivity, specificity, and accuracy were calculated for each category. Of the 56 patients who underwent arthroscopic evaluation of the TFC, 27 had TFCs that were intact at surgery. Also, 27 complete perforations and two partial defects were found at surgery. Sensitivity for detecting central degenerative perforations was 91% for both observers I and II. Sensitivity for detecting radial slitlike tears was 100% and 86% for observers I and II, respectively. Sensitivity for detecting ulnar-sided avulsions was 25% and 50% for observers I and II, respectively. MR imaging is accurate in revealing TFC perforations.