Post operative ventral hernias are common following Hartmann's procedure. There is a debate whether hernia repair is safe when performed concomitantly with colostomy closure. In this study we aimed to evaluate the outcomes of synchronous Hartmann reversal (HR) with a hernia repair, compared to a staged procedure. A retrospective multi-center study was conducted, including all patients who underwent Hartmann's procedure from January 2004 to July 2017 in 5 medical centers. Patient data included demographics, surgical data and post-operative outcome. Two hundred and seventy-four patients underwent colostomy reversal following Hartmann's procedure. In 107 patients (39%) a concomitant ventral hernia was reported during the Hartmann's reversal. Out of this cohort, 62 patients (58%) underwent hernia repair during follow-up. Thirty two patients (52%) underwent a synchronous hernia repair and 30 patients (48%) underwent hernia repair as a separate procedure. Post operative complication rate was significantly higher in the colostomy reversal with synchronous hernia repair group when compared to HR alone group (53% vs. 20%; p < 0.01; OR 4.5). In addition, severe complication rate (Clavien-Dindo score ≥ 3) was higher in the synchronous hernia repair group (25% vs. 7%). A tendency for higher hernia recurrence rate was noted in the synchronous group (56% vs. 40%). Median follow up time was 2.53 years (range 1-13.3 years). Synchronous colostomy closure and ventral hernia repair following Hartmann's procedure carries a significant risk for post operative complications, indicating that a staged procedure might be preferable.