BACKGROUND This paper explores the gender-related bilateral differences of extensor and flexor torques of the knee joint at low and high angular velocities in Iranian healthy males and females. METHODS 70 healthy subjects (29 males (26.61±4.34 yrs and 41 females with average age of 23.07±3.70 yrs)) were participated in this study. Isokinetic peak torque values for knee extensors and flexors in concentric and eccentric contraction modes were measured and flexors and extensors strength ratios (HQR) computed among both dominant and non-dominant legs in lying position at 60 and 180°.s-1angular velocities. RESULTS There was significant gender-velocity interactions detected for knee flexor to extensor strength ratios presenting that increasing velocity escaled this, ratios in females more than males (p<0.05). There was no gender- velocity-leg side interaction (p>0.05). Bilateral differences were found for eccentric flexor peak torques (p<0.05). By increasing velocity, peak torque values decreased and HQR was increased (p<0.05). CONCLUSIONS Measurement procedures including test position is an important factor when interpreting genderrelated and bilateral differences of isokinetic knee strength ratios in healthy individuals.