The aim of our investigation is to determine the shoulder rotator cuff muscles produced peak torques ratio specific to adolescent handball players, as well as, to determine the relationship between shoulder internal rotator muscles group’s strength and throwing speed in adolescent handball players. The shoulder joint motions in internal-external rotation are investigated using dynamometers system “REV – 9000” (Technogym, Italy). 16 male adolescent handball players with injury - free shoulder joints have participated in the investigation. Their median age was 14 ± 1 years, height 176 ± 7 cm and weight 63 ± 10 kg. The shoulder internal - external rotation isokinetic movements were tested in the plane of scapula at slow (60º/s) and medium (90º/s) angular velocity. The throwing speed was measured by optical equipment “Superschus” (EDV – Beratung Arbeiter, Germany). The difference between the ratios of peak torque values produced by the dominant and non-dominant arm shoulders external/ internal rotator muscles is insignificant. The shoulder external/ internal rotators maximal torques ratio for adult handball players is close to 80%. This ratio for adolescent athletes is smaller – approximately 70 %. It proves, that additional exercises must be included in the training process to develop the shoulder external rotators muscles. Our results demonstrate positive correlation between the shoulder internal rotator muscles developed peak torque at slow (60º/s) movements and the throwing speed in adolescent handball players (r = 0,83; p = 0,0002) and the peak torque of the same muscles at medium (90º/s) angular velocity and the throwing speed (r = 0,76; p = 0,002) in adolescent handball players. Strengthening of the shoulder internal rotator muscles together with the muscles-antagonists (external rotator muscles) is recommended to be included into the training process of the adolescent handball players.