Objective: The aims of this study were to compare the isokinetic forces and Hamstring/Quadriceps (H/Q) ratios in individuals with anterior cruciate ligament (ACL) injury sides and contralateral non-injured sides. Method: Twenty-three male patients with unilateral acute ACL injury were included in the study. The isokinetic extension (Ex) and flexion (Flx) forces of both knees were measured using an isokinetic dynamometer. Isokinetic tests were performed with three different angular speeds (60° s/180° s/240° s) with five repetitions for 60° s and 180° s and 15 repetitions for 240° s or concentric contraction. Results: The mean age of the patients was 25.18, the mean height was 176.81, and the mean weight was 77.12. The mean time from ACL injury to the time of measurements was 37.47±11.11 days. When the isokinetic strengths of knees with ACL injury and knees without ACL injury were examined, there was a significant difference in Ex phase at an angular velocity of 60°s (p=0.012, 95% CI: 5.95–41.54). No significant difference was detected in both Ex and Flx phases of other angular velocities (p>0.05). Conclusion: As a result, the knee with an ACL injury generates less force than the knee without an ACL injury. H/Q ratios were also outside the normal range on the ACL damaged side only at 60 s angular velocity, as expected. The absence of a significant difference in both strength and H/Q ratios at high angular velocities indicates that the movement is performed with less force than at lower angular velocities, and this situation strains the hamstring and quadriceps muscles less.