Objective To analyze the cl inical therapeutic effect of extended Sublay technique via previous incision for repairing flank hernias in comparison with routine Sublay technique. Methods Between May 2004 and May 2009, 41 patients with flank hernia were treated by extended Sublay repair via previous incision (extended Sublay repair group, n=18) and by routine Sublay repair (rountine Sublay repair group, n=23). In extended Sublay repair group, there were 11 males and 7 females with an average age of 45.2 years (range, 32-61 years); flank hernia was cuased by flank incision operation (12 patientswith surgery history of nephrectomy, adrenalectomy, and vascular procedure) and traffic accident (6 patients) with an average disease duration of 14.5 months (range, 8-23 months); and the locations were the left flank region in 11 patients (7 affected superior lumbar triangles and 4 affected inferior lumbar triangles) and the right flank region in 7 patients (5 affected superior lumbar triangles and 2 affected inferior lumbar triangles). In routine Sublay repair group, there were 14 males and 9 females with an average age of 48.7 years (range, 33-64 years); flank hernia was cuased by flank incision operation (15 patients with surgery history of nephrectomy, adrenalectomy, and vascular procedure), traffic accident (6 patients), and fall ing (2 patients) with an average disease duration of 18.2 months (range, 11-27 months); and the locations were the left flank region in 10 patients (5 affected superior lumbar triangles and 5 affected inferior lumbar triangles) and the right flank region in 13 patients (9 affected superior lumbar triangles and 4 affected inferior lumbar triangles). There was no significant difference in general data between 2 groups (P gt; 0.05). Results The mesh size in extended Sublay repair group was significantly larger than that in routine Sublay repair group [(618.2 ± 40.6) cm2 vs. (512.2 ± 36.5) cm2, P lt; 0.05 ]. There was no significant difference in hernia ring size, operation time, and hospital ization day between 2 groups (P gt; 0.05). In extended Sublay repair group, the patients were followed up 17 to 35 months (26.2 months on average) with an early compl ication incidence of 27.8% (hematomas in 2 cases, seroma in 1 case, and chronic pain in 2 cases within 1 month) and a late compl ication incidence of 0 (no hernia recurrence and abdominalwall bulge during follow-up). In routine Sublay repair group, the patients were followed up 14-35 months (24.5 months onaverage) with an early compl ication incidence of 13.0% (seroma in 1 case and chronic pains in 2 cases within 1 month) and a late compl ication incidence of 30.4% (hernia recurrence in 3 cases and abdominal wall bulge in 4 cases at 1-3 months). There was significant difference in the late compl ication incidence between 2 groups (P lt; 0.05). Conclusion Extended Sublay technique is a safe and effective approach for flank hernia repair. Making clear the anatomy of lumbar region, harvesting adequate space for mesh overlap, and effectively-fixing are critical to ideal cl inical outcomes.