Objectives: To evaluate the efficacy and safety of TS1-Cisplatin regimen in the first - line treatment of metastatic gastric cancer patients. Methods: 38 eligible patients were treated with TS1-cisplatin at Hanoi Medical University Hospital from January 2018 to December 2021. Results: Mean age was 57.4. Male: female ratio = 3.2:1. Most patients had good performance status (PS 0 or PS 1 - 84.2%). Most received dose rate from 85% to 100% of standard dose (78.9%). After six cycles, complete response rate was 13.2%, partial response rate was 42.1%. The median progression - free survival was 5.7 months. The median overall survival was 13.5 months. Neutropenia was the most common adverse event (52.6%), of which 13.1% was in grade 3 - 4. Diarrhea accounted for 36.8%, only one of which was in grade 3 (2.6%). Only one patient had hand - foot syndrome (2.6%). Conclusion: TS1-Cisplatin regimen in metastatic gastric cancer had a good response rate while being safe and tolerable.