Timing of systemic chemotherapy in patients with colorectal peritoneal carcinomatosis treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy is controversial. Preoperative systemic chemotherapy may offer benefits. The purpose of this study was to evaluate the effect of timing of systemic chemotherapy on survival. This was a retrospective cohort study. The study was conducted at a tertiary referral center. Patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy from January 2004 until June 2015 were included. The influence of patient-related, tumor-related, and treatment-related factors on survival were investigated using Cox regression models. Main outcome was overall survival. A total of 280 consecutive patients underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. In group A, 78 patients (28%) were treated with preoperative or perioperative chemotherapy, cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy. In group B, 169 patients (60%) were intentionally treated with cytoreductive surgery, hyperthermic intraperitoneal chemotherapy, and adjuvant chemotherapy. In group C, 33 patients (12%) had received their chemotherapy before peritoneal carcinomatosis was diagnosed. Median overall survival was 36.9 months (interquartile range, 20.6-79.7 mo) in group A, 43.1 months (interquartile range, 25.7-95.9 mo) in group B, and 34.0 months (interquartile range, 20.0-53.7 mo) in group C (p = 0.19). The extent of peritoneal carcinomatosis (region count of 3-5, HR = 1.58 (95% CI, 1.02-2.45), and 6-7, HR = 3.34 (95% CI, 1.66-6.72) vs 1-2 regions), a higher lymph node ratio (HR = 7.96 (95% CI, 2.16-29.31)), and cycles of systemic chemotherapy (0 cycles, HR = 2.52 (95% CI, 1.48-4.29)) and partial chemotherapy (HR = 2.15 (95% CI, 1.27-3.65) vs complete chemotherapy) were associated with poorer overall survival. Selection bias is present because of the retrospective design of this study. Timing of systemic chemotherapy does not appear to have impact on survival in patients with colorectal peritoneal carcinomatosis undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.