Objective: To investigate the efficacy of laparoscopic hyperthermic intraperitoneal perfusion chemotherapy combined with intraperitoneal and systemic chemotherapy (HIPEC-IP-IV) in the treatment of peritoneal metastases from gastric cancer (GCPM). Methods: This was a descriptive case series study. Indications for HIPEC-IP-IV treatment include: (1) pathologically confirmed gastric or esophagogastric junction adenocarcinoma; (2) age 20-85 years; (3) peritoneal metastases as the sole form of Stage IV disease, confirmed by computed tomography, laparoscopic exploration, ascites or peritoneal lavage fluid cytology; and (4) Eastern Cooperative Oncology Group performance status 0-1. Contraindications include: (1) routine blood tests, liver and renal function, and electrocardiogram showing no contraindications to chemotherapy; (2) no serious cardiopulmonary dysfunction; and (3) no intestinal obstruction or peritoneal adhesions. According to the above criteria, data of patients with GCPM who had undergone laparoscopic exploration and HIPEC from June 2015 to March 2021 in the Peking University Cancer Hospital Gastrointestinal Center were analyzed, after excluding those who had received antitumor medical or surgical treatment. Two weeks after laparoscopic exploration and HIPEC, the patients received intraperitoneal and systemic chemotherapy. They were evaluated every two to four cycles. Surgery was considered if the treatment was effective, as shown by achieving stable disease or a partial or complete response and negative cytology. The primary outcomes were surgical conversion rate, R0 resection rate, and overall survival. Results: Sixty-nine previously untreated patients with GCPM had undergone HIPEC-IP-IV, including 43 men and 26 women; with a median age of 59 (24-83) years. The median PCI was 10 (1-39). Thirteen patients (18.8%) underwent surgery after HIPEC-IP-IV, R0 being achieved in nine of them (13.0%). The median overall survival (OS) was 16.1 months. The median OS of patients with massive or moderate ascites and little or no ascites were 6.6 and 17.9 months, respectively (P<0.001). The median OS of patients who had undergone R0 surgery, non-R0 surgery, and no surgery were 32.8, 8.0, and 14.9 months, respectively (P=0.007). Conclusions: HIPEC-IP-IV is a feasible treatment protocol for GCPM. Patients with massive or moderate ascites have a poor prognosis. Candidates for surgery should be selected carefully from those in whom treatment has been effective and R0 should be aimed for.