We conducted a retrospective comparative study on feasibility of S-1/oxaliplatin(SOX)therapy and S-1/cisplatin therapy with short hydration(SP-SH)for gastric cancer in the outpatient setting. The subjects were patients with gastric cancer aged younger than 75 years who underwent SOX or SP-SH therapy at our hospital. There were 22 patients in the SOX group and 30 patients in the SP-SH group. Both the groups received the first course during hospitalization and then received the subsequent courses in the outpatient section. Evaluation items for each therapy included the treatment rate in the outpatient setting, number of re-hospitalization cases, relative dose intensity(RDI), and adverse events. The treatment rate in the outpatient setting was 100%(22/22)in the SOX group and 96%in the SP-SH group(26/27). Re-hospitalization cases included 1 case of loss of appetite in the SOX group and 1 cases of loss of appetite and 2 cases of febrile neutropenia(FN)in the SP-SH group. The median values of the RDI were 86% with S-1 and 85% with oxaliplatin in the SOX group and 92% with S-1 and 80% with cisplatin in the SP-SH group. The SP-SH group had a higher proportion of neutropenia cases of Grade 3 or higher(SP-SH 33% v. s SOX 5%, p=0.012). The SOX group showed a higher proportion of loss of appetite cases for all the Grades(SOX 86% v. s SP-SH 50%, p=0.007)and peripheral neuropathy cases(SOX 64% v. s SP-SH 23%, p=0.003). It was considered that SOX and SP-SH therapies can be treated in the outpatient section, although the occurrence of loss of appetite and FN must be considered.