Background: Although concomitant pulmonary vein isolation (PVI) is used more frequently than the Cox-maze procedure, which is currently the gold standard treatment for AF, data on the comparative effectiveness of the two procedures after concomitant mitral valve (MV) surgery are still limited. Objective: We conducted a systematic review to identify randomized controlled trials (RCT) and observational studies comparing the mid-term mortality and recurrence of atrial fibrillation (AF) after concomitant Cox-Maze and PVI in patients with AF undergoing MV surgery based on 12-month follow-up. Methods: Medline, EMBASE databases, and the Cochrane Library were searched from 1987 up to March 2022 for studies comparing concomitant Cox-Maze and PVI. A meta-analysis of RCTs was performed to compare the mid-term clinical outcomes between these two surgical ablation techniques. Results: Three RCTs and 3 observational studies meeting the inclusion criteria were included with 790 patients in total (532 concomitant Cox-Maze and 258 PVI during MV surgery). Regarding AF recurrence, estimate pooled across the 3 RCTs indicated large heterogeneity and high uncertainty. In the largest and highest quality RCT, 12-month AF recurrence was higher in the PVI arm (RR=1.58, 95%CI 0.91-2.73). In 2 out of 3 higher quality observational studies, 12-month AF recurrence was higher in PVI than in Cox-Maze arm (estimated adjusted probabilities 11% vs. 8% and 35% vs. 17%, respectively). RCTs demonstrated comparable 12-month mortality between concomitant Cox-Maze and PVI, while observational studies demonstrated survival benefit of Cox-Maze. Conclusions: Concomitant Cox-Maze in AF patients undergoing MV surgery is associated with better mid-term freedom from AF when compared to PVI with comparable mid-term survival. Large observational studies suggest that there might be a mid-term survival benefit among patients after concomitant Cox-Maze. Further large RCTs with longer standardized follow-up are required in order to clarify benefits of concomitant Cox-Maze in AF patients during MV surgery.