Next to ACTS-GC (Adjuvant Chemotherapy Trial of S-1 for Gastric Cancer), adjuvant chemotherapy with S-1 is the standard treatment for stage II or III gastric cancer patients.In this study, we retrospectively examined the continuity and adverse reaction of S-1 adjuvant chemotherapy in 30 gastric cancer patients who visited our hospital from 2007 to 2008, and compared them with those of patients treated with ACTS-GC. Whereas the persistent rate of S-1 adjuvant chemotherapy for one year in ACTS-GC was 65.8%, it was 86.7% in our hospital.The RP (Relative performance) value in cases who completed S-1 adjuvant therapy for one year in ACTS-GC and for one year in our hospital was 81.2% and 88.5%, respectively. Grade 3/4 adverse events in our hospital were leukopenia (3.3%), neutropenia (16.7%), and anorexia(6.7%). In conclusion, our hospital has shown a far greater continuity with S- 1 adjuvant chemotherapy than with ACTS-GC, a result suggesting that S-1 adjuvant chemotherapy is feasible in clinical practice.