Purpose To evaluate the effect of biceps tenotomy on humeral migration and clinical outcomes in patients who underwent arthroscopic rotator cuff (RC) repair. Methods This is a retrospective study of 60 patients who underwent arthroscopic RC repair. Patients were divided into two groups, whether they underwent concomitant biceps tenotomy or not. The group underwent concomitant biceps tenotomy, tenotomy ( +), or not, tenotomy (-). Clinical and functional outcomes were performed using the American Shoulder and Elbow Surgeons (ASES), the University of California-Los Angeles (UCLA) scoring system. Radiological evaluation was performed in X-rays and magnetic resonance imaging (MRI), measuring the acromiohumeral distance (AHD), humeral migration (HM) and upper migration index (UMI). Results There was no significant difference between the groups in terms of patient characteristics. The follow-up period was 30.9 ± 8.7 months in the tenotomy ( +) group and 34.9 ± 8.2 months in the tenotomy (-) group with no significant difference. Postoperative ASES score improved significantly in the tenotomy ( +) group compared to the tenotomy (-) group (91.2 ± 4.7, 80.8 ± 18.7, respectively, p = 0.005). There was a significant difference in postoperative AHD, HM and UMI values (MRI; p = 0.003, p = 0.017, p = 0.025; X-ray; p = 0.049, p = 0.002, p = 0.010, respectively). The post–pre difference increase of AHD [MRI for tenotomy( +): 0.14 ± 0.86 and tenotomy(-): 0.91 ± 0.85, p = 0.001; X-ray for tenotomy( +): 0.61 ± 0.43 and tenotomy(-): 1.12 ± 0.7, p = 0.001] and UMI [MRI for tenotomy( +): 0.005 ± 0.05 and tenotomy(-): 0.04 ± 0.06, p = 0.006; X-ray for tenotomy( +): 0.01 ± .064 and tenotomy(-): 0.12 ± 0.37, p = 0.110] values were higher in the tenotomy (-) group compared to the tenotomy ( +) group while HM values decreased more in the tenotomy (-) group. [MRI for tenotomy ( +): -0.19 ± 1.07 and tenotomy (-): -0.79 ± 1.52, p = 0.079; X-ray for tenotomy ( +): -0.27 ± 0.54 and tenotomy (-): -1.006 ± 1.83, p = 0.040]. Conclusion After short-term follow-up, the humeral head was positioned higher in patients who underwent LHBT tenotomy compared to patients without tenotomy. However, it seems to affect clinical outcomes during this period positively. Level of Evidence Level 3