BackgroundTo evaluate the incidence of incisional hernia (IH) after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) and its impact on health-related quality of life (HRQoL).MethodFrom June 2006 until June 2016, 152 patients were followed after CRS + HIPEC at Aarhus University Hospital, a single national center. Patients were seen postoperatively in an outpatient clinic at 3, 6, 12, 18, 24, 36 48, and 60 months. Clinical examinations at these follow-up visits were used to evaluate IH events prospectively. The incidence of IH was estimated using competing risk analysis and is presented as the cumulative incidence proportion (CIP). We expected the incidence to be 15% at 12 months. HRQoL was assessed at 12 months by the Short Form (SF-36) questionnaire, which we used to compare patients with an IH to patients without an IH.ResultsThe median follow-up time was 16.6 months [range 0.9–62.0]. During this period, 14/152 (9.2%) patients developed an IH. The 1-year CIP was 5.9% [95% CI 2.9; 10.4] (n = 8), and the 2-year CIP was 9.2% [95% CI 5.3; 14.5] (n = 14). Patients with an IH were significantly older (67 years [range 48–72]) compared to patients without IH (60 years [range 24–75], p ≤ 0.01). The rate of postoperative complications between patients with and without IH was comparable, except that a greater proportion of patients with IH had a fascial dehiscence (21.4%) compared to patients without an IH (3.6%). Reponses to the SF-36 show that patients with an IH report lower HRQoL with regard to Role-physical (mean difference − 32.9 [95% CI − 60.6; − 5.3]) and Role-emotional (mean difference − 20.2 [95% CI − 43.4; 3.1]), meaning a reduction in work and daily activities due to their physical and psychological health. We found no general decrease in HRQoL.ConclusionCRS + HIPEC do not increase the risk of IH as measured within 12 months postoperatively, contrary to expectations. However, patients with an IH report a limitation in daily activities, which can best be explained by changes in physical and psychological health. A larger cohort from multiple centres is necessary to verify our findings.