Purpose: We investigated the safety of triple combination therapy by addition of Paclitaxel (PTX) to Cisplatin (CDDP) and 5-fluorouracil (5-FU) combination therapy, which was considered the conventional standard therapy for patients with unresectable / recurrent gastric cancer. Material and Methods: The doses of PTX and CDDP were fixed at 80 and 50 mg/m2. They were administered on days 1 and 8, followed by a resting period of 20 days. 5-FU 300 mg/m2 at a maximum dose of 500 mg/m2 was administered at levels 0 and 2, respectively, and the dose was increased by 100 mg/m2 until the maximum tolerated dose (MTD). It was administered on days 1 - 5 and 8 - 12, followed by a resting period of 16 days Results: Twelve patients enrolled in this study. Of them, three patients were excluded from evaluation because treatment continuation was not feasible. There were 4 leukopenia and 7 neutropenia cases with hematological toxicity at grade 3 or higher. They were observed at all dose levels, but no case showed infection. In terms of non-hematological toxicity at grade 3 or higher, there were two patients with nausea and vomiting and two patients with diarrhea, one patient with mucositis, one patient with anorexia. All patients with non-hematological toxicity at grade 3 or higher were at level 2. The dose-limiting toxicity (DLT) was observed at level 2, and 5-FU at 400 mg (level 1) was adopted. Conclusions: We proved in this study that PTX, CDDP, and 5-FU combination chemotherapy was a safe treatment.