Introduction: The core muscles of trunk are activated before movements of upper and lower limbs. Current evidence suggests that lose of stability in core region predisposes to second injury and appropriate exercise may reduce the risk of reinjury. This aim of this study was to evaluate the effect of eight weeks core stability exercises on dynamic balance, function and strength in athletes after anterior cruciate ligament reconstruction.
 Methods: This study was a randomized clinical trial. 26 athletes with a history of anterior cruciate ligament reconstruction were purposefully selected and randomly divided into experimental and control groups. The experimental group performed core stability exercises for eight weeks and the control group performed their daily exercises. Dynamic balance, isometric strength and function were meaured using Y balance test, hand held dynamometer and hop tests. Data were analyzed using SPSS vrsion16 software. Independent t-test was used to compare demographic characteristics and Mixed Repeated Measures ANOVA was used to compare the means of the two groups (p≤.05).
 Results: The results of the present study showed significant improvement in dynamic balance (F=143.92, P=0.000), single-leg hop (F=68.25, P=0.000), triple hop (F=14.02, P= 0.001), knee flexor strength (F=50.21, P=0.000) and knee extensor strength (F=54.72, P=0.000) in the experimental group after eight weeks of core stability exercises.
 Conclusion: Based on the results of present study, it is suggested to the specialists and trainers involed in the rehabilitation of athletes to use comprehensive and useful core stabilization exercises in the rehabilitation stages of knee injuries.