Objective: The aim of this study was to present a review of intraarticular ganglia of the knee. Materials: Cases of intraarticular ganglia of the knee were isolated from a group of 1405 consecutive patients referred for MR imaging examinations of the knee. Diagnoses were conþrmed by means of a histological study after arthroscopic or surgical excision. Results: 14 pts (10 men and four women) had intraarticular ganglia of the knee. 3 ganglia were found in Hoffañs fat pad, 5 were associated with the anterior cruciate ligament, 5 were associated with the posterior cruciate ligament, and one was associated with the ligament of Humphrey. Pain was the most common complaint. Symptoms grew worse with activity in 9 pts. There was associated limited knee extension in 4 cases and limited knee ßexion in 3 cases. One of the three pts with ganglia in Hoffañs fat pad had a palpable mass on physical examination. The cysts were ßuidþlled, with low T1-w and high T2-w signal intensity. 10 cases demonstrated peripheral thin rim enhancement on fat-suppressed contrast-enhanced T1-w SE images. Grad echo sequences were useful in excluding areas of hemosiderin. Conclusion: Intraarticular ganglia of the knee have been found to occur commonly, with a prevalence of 1.% in the present series. The clinical presentation of intra-articular ganglion cyst is varied according to its intra-articular location. Radiologists should be aware of this entity and its defferential diagnoses. The contrast-enhanced sequences allow intraarticular ganglia to be distinguished from PVNS, synovial hemangioma and synovial sarcoma.