PURPOSE: To determine the presence of cruciate ligament tears following avulsion injuries involving the ACL and PCL, and to correlate the findings with those of surgery. MATERIALS AND METHODS: Between March 1997 and May 2002, avulsion injury involving the ACL or PCL was diagnosed in 19 patients. Ten of these [8 males and 2 females aged 10-51 (avergae, 27.7) years] were included in this study. We assessed the presence of cruciate ligament tears at MR imaging, correlating the findings with those of surgery. Associated intra-articular injuries, treatment methods and follow-up results were also evaluated. RESULTS: Among Seven patients with ACL avulsion injury, this was assessed at MR imaging as complete tear (n=1), partial tear (n=5), or intact (n=1), while all MR images of PCL avulsion injury (n=3) showed that this was partial tear. All imaging findings corresponded with the surgical findings. In four patients there was associated knee injury involving, respectively, tears of the medial meniscus, lateral meniscus, PCL and MCL, and popliteal ligament. CONCLUSION: Our findings showed that with one exception, patients with avulsion injury of the ACL or PCL had suffered either a partial or complete tear. MR imaging may be useful in the diagnosis of tears of the cruciate ligament which have not been noticed at surgery or arthroscopy in avulsion injuries involving the ACL and PCL.