Background: Several systematic reviews have reported on the conservative treatment of full-thickness rotator cuff tears; however, clinical results of this treatment still remain determined. Methods: PubMed, Cochrane Library, PEDro, and CINAHL databases were systematically searched for randomized clinical trials and observational studies. Two independent researchers reviewed a total of 2,981 articles, 28 of which met the criteria for inclusion in the study. Clinical outcome measures included Constant score, visual analog scale score for pain, range of motion, and short-form 36. The meta-analysis used a linear mixed model weighted with the variance of the estimate. Results: The meta-analysis showed a significant improvement after surgery. Pain score is 26.2 mm (1 month) to 26.4 mm (3 months) and 24.8 mm (12 months) (P<0.05); active abduction: 153.2º (2 months), 159.0º (6 months), 168.1º (12 months) (P<0.05); Constant score: 67.8 points (2 months) to 77.2 points (12 months) (P<0.05); short-form 36 “vitality” section: 57.0 points (6 months) and 70.0 points (12 months) (P<0.05). Conclusions Our data confirmed the effectiveness of conservative treatment in patients with full-thickness rotator cuff tears 12 months post-intervention. The results suggest that conservative treatment for patients with full-thickness rotator cuff tears should be the first line of treatment before considering surgery.