Te purpose of this study was to evaluate the hamstring to quadriceps peak torque ratio of a healthy leg in case of unilateral anterior cruciate ligament injury. There were 20 patients (8 females, 12 males). The average age of patients was 31.5 years. Isokinetic evaluation of the hamstring and quadriceps peak torques was performed with the system 3 Biodex isokinetic dynameter (180 degrees/ s). The average H/QR was 50% thus 20% below its lower normative limit. There were no statistically significant differences between both females and males H/QR and age. Since the pathological hamstring to quadriceps peak torque ratio increases a risk of an anterior cruciate ligament injury its evaluation should be a standard procedure in high risk sports.