We studied the influencing of normobaric hyperoxia one hour daily during 14 and 28 days on the bone metabolism for 3- and 12-monthly Wistar male-rats (n =80). It was shown, that breathed normobaric gas mixture with 90% O2 during 14 days significant reducing of C-terminal propeptides of type I collagen levels for 36%, an increasing piridinolin levels for 37% and concentration of C-terminal telopeptides of type I collagen for 8% in the blood serum. We found reliable decreas­ing the concentration of piridinolin levels for 27% in adult rats in the same conditions. The C-terminal propeptides of type I collagen levels did not change in any of the groups’ research. We believe that 14 days normobaric hyperoxia (90%) in young animals accompanied by violation of collagen synthesis. The adult rats were more stable and had no changes after influence the two hyperoxia levels.