Background: Urinary system resections and reconstructions are needed in peritoneal carcinomatosis due to abdominal malignancies. The effect of hyperthermic intraperitoneal chemotherapy on these urological procedures after reconstruction remains uncertain. The aim of the study is to evaluate major urological interventions during cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in complex abdominal malignancies with peritoneal carcinomatosis. Methods: Forty-four cases underwent surgical intervention related to the urinary system among 208 cases who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy because of peritoneal carcinomatosis. Urinary system procedures performed in these patients (radical-partial cystectomy, partial ureter resection ureteroneocystostomy, ureteroureterostomy, nephrectomy) were evaluated in terms of postoperative morbidity–mortality and survival. Results: Urinary system resections were performed during cytoreductive surgery in a total of 44 cases. The mean age was 54 years (20–73). Patients were diagnosed with peritoneal carcinomatosis due to colorectal cancer in 21 (47.8%), ovarian cancer in nine (20.4%), sarcomatosis in five (11.4%), cervical cancer in four (9%) and other cancers (mesothelioma, uterus, breast, gastric) in five (11.4%) cases. Total nephrectomy was performed in three cases and partial nephrectomy in one case. Cystectomy was performed in 21 cases; 16 of these were partial and five were total cystectomies. Ureteroureterocystostomy with double J was performed in four cases and ureteroneocystostomy in 12 cases. While Clavian–Dindo grade 3–4 complications were seen in nine cases (20.4%), three cases (6.8%) became exitus during the first 30-day follow-up. Conclusions: Although urinary system involvements have been regarded as inoperable in the past, we think that with adequate experience radical urinary interventions performed in suitable patients can be carried out with acceptable morbidity and mortality as seen in our series.