This study investigated the degrees of surgical invasion for arthroscopic rotator cuff repair and open rotator cuff repair by evaluating the serum levels of C-reactive protein, hemoglobin, and interleukin-6. The study participants were 17 patients (group A) who underwent arthroscopic rotator cuff repair and 15 patients (group O) who underwent open rotator cuff repair by the same surgeon. The difference in the size of the rotator cuff tear between the 2 groups was not significant (P > .05). No significant differences were recorded in the postoperative serum levels of C-reactive protein and hemoglobin between the 2 groups (P > .05). The mean postoperative serum level of interleukin-6 was significantly lower in group A than in group O (P < .01). Our findings indicate that arthroscopic rotator cuff repair is less invasive than open rotator cuff repair.