The sodium-to-calcium ratios were determined by INAA in sections of human bone. The values found in three age groups of male individuals were as follows: 21–30 years: Na/Ca ratio of 0.01858, 41–50 years: Na/Ca ratio of 0.02117, >60 years: Na/Ca ratio of 0.002208. The differences are discussed considering former results of the authors concerning the Na–to–Ca ratio in the bone mineral.