Background: Hyperthermic intraperitoneal chemotherapy (HIPEC) following cytoreductive surgery (CRS), performed using closed-abdomen technique (CAT), may affect intraabdominal pressure (IAP). High IAP may increase postoperative complications due to decreased venous return and hypoperfusion to vital organs. Elevated core body temperature (CBT) may cause multiorgan dysfunction. Low IAP or CBT could result in suboptimal HIPEC and potentially translate into early disease recurrence. The aim of the present study is to identify possible correlations between IAP or CBT and postoperative complications. Patients and Methods: Continuous intraabdominal pressure measurement was performed by intraabdominal catheter. Inflow temperature was set at 44 °C, and mean perfusate temperature was 42 °C. CBT was measured continuously in the distal esophagus. We compared the rate of postoperative complications between the low IAP group (2–10 mmHg, n = 28), target IAP group (10–20 mmHg, n = 71), and high IAP group (20–34 mmHg, n = 16) as well as with CBT as a continuous variable. Results: 115 patients were included in the study. There was no difference between IAP groups in terms of age, gender, primary diagnosis, operative peritoneal cancer index, CBT, or operative time. There was no correlation between IAP and postoperative complications or with prolonged hospital stay. On multivariate analysis, elevated mean CBT was a positive predictor of postoperative complications (p = 0.035). Conclusions: IAP level during closed-abdomen technique HIPEC is not associated with postoperative complications. However, elevated CBT may increase postoperative complications.