Background: The repetitions attributed to the shoulders, mainly to the internal rotator muscles, during the throwing movements increase the risk of injury. Thus, it is necessary to ensure an adequate balance between the internal rotator (IR) muscles and their antagonists, external rotators (ER). Objective: To describe the strength and muscle balance of internal and external shoulder rotators in handball players. Methods: Descriptive sectional study with 58 handball athletes. Muscle function was assessed by the isokinetic dynamometer, the variables analyzed were the peak torque (TP) between the right and left shoulders and the antagonist/agonist ratio. Results: The lowest TP value in women ranged from 2.18 at angular speed of 300º/s (ER) to 33.0 at angular speed of 60º/s (IR). For the ER / IR ratio, the lowest value was 0.11 and the highest 0.79. For males, the lowest PT value was 27.5 (ER) at an angular speed of 300º / s, a higher value of 69.5 (IR) at angled speed of 60º/s. The RE / IR ratio ranged from 0.54 to 0.71. Conclusion: It was shown that the highest values of strength are in the dominant shoulder, for both sexes, which is considered normal. However, we also found a deficit in the ER / IR ratio above the cutoff point indicated in the literature, suggesting a significant muscle imbalance.Keywords: shoulder, handball, isokinetic dynamometer.