It was assumed that the temperature at which caffeine is consumed may cause changes in the mechanical and morphological properties of bones and affect the bone metabolism of pregnant female. The aim of the study was to assess the effect of caffeine used at different temperatures on selected morphological and mechanical properties of the femur as well as biochemical indicators of bone formation in female rats in pregnancy. It was use test solution at the temperature 10, 25 and 45ºC from 8 to 21 day during pregnancy, once a day. It was found that the temperature of administrated caffeine may have an effect on changing the morphometric properties and on the bone metabolism of pregnant female rats. The application of caffeine solution, was administrated at 10ºC caused the most constrained growth of the femur and weakened resistance to load, and caused increased susceptibility to cracks. Analysis of bone metabolism indicators showed that caffeine administered in the form of a solution at 10ºC and 25ºC caused the most negativity effects for bone formation and bone turnover indicators. The administration of caffeine at 10ºC causes the largest negative changes in bone morphological and strength indicators and hasn’t a beneficial effect on the bone metabolism of pregnant female rats