Survival of Stage IV gastric cancer is poor. We report 2 cases of Stage IV gastric cancer with positive peritoneal washing cytology or peritoneal dissemination that were successfully treated with gastrectomy and hyperthermic intraperitoneal chemotherapy( HIPEC)followed by systemic chemotherapy. Case 1: A 59-year-old woman. She was diagnosed with advanced gastric cancer and underwent gastrectomy with HIPEC. Her peritoneal washing cytology was positive during the gastrectomy. After the surgery, she underwent chemotherapy consisting of 8 courses of combination S-1 plus CPT-11 and 19 courses of PTX. It has been 5 years and 7 months since she had the surgery and she survives without recurrence of the cancer. Case 2: A 60-year-old woman. She was diagnosed with advanced gastric cancer and peritoneal dissemination(peritoneal cancer index: 3 points). She underwent gastrectomy, hemi-colectomy, and HIPEC. After the surgery, she underwent chemotherapy, 35 courses of combination S-1 plus PSK/DOC, and 13 courses of S-1 plus PSK. It has been 5 years since her surgery and she survives without exacerbation of the cancer. These cases suggest a gastrectomy and HIPEC followed by systemic chemotherapy may represent an effective treatment for advanced gastric cancer with a small amount of peritoneal metastasis.