Bone metabolic disorder after gastrectomy is a silent complication, and has potential of severely disturbing quality of life. However, the awareness of this complication is not enough in clinicians. We examined the influence of gastrectomy on bone metabolism using the investigation of clinical cases and experiments with rat surgical models. We discussed the influence of the volume of resected stomach and the reconstructed route of food passage. Bone metabolic disorders were observed in 30% of patients after gastrectomy. They were milder in cases after proximal gastrectomy compared with total gastrectomy(p=0.110), and segmental/local gastrectomy compared with distal gastrectomy(p=0.080), in cases with physiological route of foods passing compared with non- physiological route(p=0.091). Similar results were observed in the experiments with rat surgical models. Both of the volume of the remnant stomach and the reconstructed food passing route are correlated with bone metabolic disorders after gastrectomy.