Abstract The between-person variation in transcortin activity is related to early diabetes in men. This prompted a study of the biochemical factors related to this between person variation. Complete correlation matrices were calculated between the cortisolbinding index (CBI), a parameter of transcortin activity, and 15 anthropometrie or biochemical factors. The major part of the between-person variation in transcortin activity remained unaccounted for. In men, small positive correlation coefficients were found between CBI and serum alcaline phosphatase activity, serum uric acid, serum cholesterol or serum calcium levels, while small negative correlations were found between CBI and body weight or age. The women under study were much younger; the only important correlation found in this younger group was between CBI and total serum protein levels. The CBI also correlated with the serum sialic acid level both in men and women.