Purpose The aim of the present study was to prospectively evaluate the elbow flexion and supination strengths and the functional outcomes of patients following arthroscopic rotator cuff repair combined with simultaneous biceps tenodesis. Methods 19 patients who underwent arthroscopic rotator cuff repair and biceps tenodesis with at least 24 months of follow-up were included. Patients were evaluated using a visual analog scale (VAS) for bicipital groove pain, American Shoulder and Elbow Surgeons (ASES), and constant scores (CS), biceps apex distance (BAD), elbow flexion, and supination strengths. Results The VAS for biceps groove measurement averages in the postoperative 6th, 12th, and 24th months was lower in comparison to preoperative data and was considered to be statistically significant (p < .05). The constant score, an average of all postoperative measurements and scores, was found to be higher than preoperative values and was considered to be statistically significant (p < .01). There was a significant difference in the operated and non-operated forearm supination and elbow flexion muscle strength measurements at the postoperative 3- and 6-month follow-ups (p < .01). Conclusion Arthroscopic biceps tenodesis into the anchors of the lateral row in combination with rotator cuff repair provides an increase in the strength of elbow flexion and forearm supination, while decreasing pain.