A 49-year-old man was admitted to our hospital with back pain, appetite loss, and body weight loss in January 2009. Gastroduodenal endoscopy, abdominal computed tomography( CT), and magnetic resonance imaging( MRI) revealed type 4 advanced gastric cancer( signet-ring cell carcinoma) with multiple lymph node( No. 16 LNs), right adrenal gland, and multiple bone metastases. Between February 2009 and April 2011, 20 courses of S-1( 80 mg/m2) plus CDDP( 60 mg/m2) and zoledronic acid hydrate (4 mg/body) were administrated. Since May 2011, S-1 (70 mg/m2) and zoledronic acid hydrate( 4 mg/body) have been continued. The lymph node and adrenal gland metastases showed a complete response( CR), and the gastric tumor showed a partial response; however, the bone metastases did not show CR or progressive disease (PD) for 4 years after initiation of therapy. Chemotherapy with zoledronic acid hydrate is considered as a useful therapeutic option for advanced unresectable gastric cancer with multiple bone metastases.