The objectives of this study were to use magnetic resonance (MR) imaging to evaluate the prevalence, size, location, and clinical relevance of tendon rerupture following complete repair of full-thickness rotator cuff tear (RCT). A total of 78 surgically proven full-thickness rotator cuff tears in 74 patients were retrospectively included in the study. Clinical assessment was performed using the University of California at Los Angeles score. Postoperative MR imaging was evaluated to determine prevalence, size, and location of tendon rerupture. At a mean 48.4 months' follow-up, 62 shoulders (79.5%) had favorable outcomes and 45 shoulders (57.6%) showed rerupture on MR imaging studies. Reruptures were significantly more prevalent among patients with intermediate-to-bad outcomes (81.3%), with surgically demonstrated two-tendon tears (78.9%) or three-tendon tears (100%), and with preoperative fatty degeneration of the supraspinatus muscle greater than 1 (91.6%). Reruptures were also significantly larger in those subgroups. Complete repair of RCT of all sizes may have favorable outcomes in a significant proportion of patients in spite of a high prevalence of reruptures. Preoperative tear size and degree of muscle fatty degeneration influence the prevalence and rerupture size. After repair of supraspinatus tears, reruptures tend to invade the posterior aspect of the tendon.