To correlate morphologic and magnetic resonance (MR) imaging findings in hamstring injury with short-term prognosis and convalescence interval (CI). A retrospective study of 14 professional athletes with hamstring injury was performed. The injuries were categorized according to muscle group involved, percentage of cross-sectional area affected, location, and signal intensity on T1- and T2-weighted spin-echo images. Longer CIs (> 6 weeks) were seen in injuries with complete transection, greater than 50% cross-sectional muscle involvement, ganglionlike fluid collections (long T1 and T2), hemorrhagelike signal intensity (short T1 and T2), distal myotendinous junction tears, and deep muscular tears. Shorter CIs (< 5 weeks) were seen in superficial muscle injuries and muscle belly injuries that involved small cross-sectional areas of the muscle. Prediction of CI for high-performance athletes with complete hamstring injury may be accomplished with use of MR imaging and poor prognostic factors.