Objectives: To learn how high concentration in hyperbaric oxygen therapy (HBO) acts on the expression of genes related to bone metabolism in osteoblast cell lines and human trabecular bone. Material and methods: The differential expression of several genes related to bone metabolism (SOST, RUNX2, MMP14, OPG, HIF-1α and SIRT1) in two human osteoblastic cell lines (Saos and Super-Saos) and in human trabecular bone fragments subjected to one, three or five HBO sessions (90 minutes, 100% oxygen; 2.3 atmospheres). In each experiment, a control that did not receive HBO was used. Results: We did not find significant differences after HBO in the expression of the genes studied, neither in the cells nor in trabecular bone. Only in the Super-Saos cell line the expression of OPG after 5 sessions of HBO decreased 6 times with respect to that of the control group (2-ΔCt Ct of 72; p=0.01). Conclusions: High concentration oxygen in the hyperbaric chamber (HC) does not seem to influence the expression of genes related to bone metabolism.