In this study, a detailed analysis was conducted concerning postoperative (according to Clavien-Dindo classification) and long-term outcome (disease-free and overall survival) in a single-centre cohort of patients with FIGO III or IV after primary cytoreductive surgery with maximum surgical effort to achieve complete macroscopic tumour removal. Special emphasis was put on the impact of the individual surgical interventions, which were applied to achieve complete tumour removal. For judgement of surgical complexity, the Surgical Complexity Score (SCS) was applied. Age, surgical complexity and diabetes were identified as parameters, which significantly increase the risk of major complications or death within 30 days after surgery. Considering the individual surgical interventions, abdominal peritoneum stripping and large bowel resection were significantly correlated with increased risk for morbidity and mortality within 30 days after surgery. No association was observed for other individual surgical steps. Furthermore, surgical complexity also had an impact on long-term survival. Multivariate analysis for DFS and OS revealed age, SCS and, particularly, small bowel resection has significant factors determining long-term outcome for patients. Intriguingly, in this cohort, incomplete cytoreduction did not negatively impact overall survival in multivariate analysis. A detailed analysis of patients with complete vs. incomplete cytoreduction with and without small bowel resections showed best survival for patients with complete CRS without small bowel resection. Patients with small bowel resection had significantly worse survival, even if complete tumour removal was achieved.