Background: The purpose of this phase I study is to determine the recommended dose (RD) of everolimus (E), an mTOR inhibitor, in combination with capecitabine (XEL) and oxaliplatin (OX) and to explore feasibility of EXELOX at the RD in advanced gastric cancer (AGC). Methods: The standard 3+3 method was used to determine the RD of 3-weekly EXELOX during the first cycle. The doses of each drug [E (mg/day, D1-D21)/XEL (mg/m²/day, D1-D14)/OX (mg/m², D1)] were as follows: level 1, 7.5/1600/100; level 2A, 7.5/1,600/130; level 2B, 7.5/2,000/100; level 3A, 10/1,600/130; level 3B, 10/2,000/100; level 4, 7.5/2,000/130. Results: During the first cycle of chemotherapy, no dose limiting toxicity (DLT) was noted in each cohort of 3 patients (pts) at dose levels 1-3A. At dose level 3B, 1 DLT (delay of the next cycle over 3 weeks because of Gr2 thrombocytopenia and Gr2 AST) was observed out of 6 pts. At dose level 4, DLTs (Gr3 fatigue and Gr4 thrombocytopenia) were found in 2 out of 3 pts. However, with frequent dose delay or reduction in subsequent cycles, the actual dose intensity of XELOX during the first 3 cycles was not higher at dose levels 2 or 3 than at dose level 1. Accordingly, dose level 1 was finally considered more suitable to maintain the actual dose intensity over chemotherapy cycles. At dose level 1, with no DLT during the first 3 cycles in 3 more pts accrued to confirm the safety, 12 additional pts were enrolled in the extension cohort to explore feasibility of EXELOX in the aspect of efficacy. Among 16 patients with measurable disease at dose level 1, 8 (50%) pts achieved a confirmed PR, 7 (44%) had SD, and 1 (6%) showed PD as a best response. With a median follow-up period of 12 months (range 4.9–12.8 months), the median progression-free survival and overall survival were 5.5 and 8.1 months, respectively at dose level 1. Conclusions: In this study, the doses of XEL (1,600 mg/m²/day), OX (100 mg/m²), and E (7.5 mg/day) were recommended with good tolerability for the 3 weekly EXELOX combination as the 1st line chemotherapy for AGC. The efficacy of this combination needs to be evaluated in future trials. Clinical trial information: NCT01049620.