Six athletes who throw and one shot-putter who underwent elbow arthroscopy were found to have an area of chondromalacia involving the posterolateral aspect of the olecranon. Preoperative symptoms were pain and tenderness to palpation over the lateral edge of the olecranon. On physical examination, range of motion was full or only slightly decreased (< 5 degrees) in five patients; coexistent loose bodies were also noted in two patients having a 20 degrees loss of extension. None of the patients exhibited ligamentous laxity to valgus stress testing of the elbow. During arthroscopy, the involved area was distinct from the bare area of the olecranon. This area was found as an isolated lesion in only one of seven patients; localized synovitis was noted in five patients, olecranon osteophytes in three, and loose bodies in two. A reciprocal lesion on the articular surface of the humerus was not identified in any patient. During arthroscopy, the lesion was debrided to a stable margin, and all associated pathologic conditions were addressed. Six of the seven athletes were able to return to their sport at premorbidity levels with this approach. This area of trochlear chondromalacia has not been previously described and, in our study, occurred in individuals whose elbows were subjected to repetitive valgus stress with lateral compression.