Hematologic variables were measured in 240 apparently healthy infants ranging from 1-12 months of age attending a well baby clinic. There were 20 infants for each month of age. Hematologic parameters were measured in each infant by Coulter Counter Model S. Serum iron, total iron binding capacity, free erythrocyte protoporphyrin (FEP) and serum ferritin levels were measured in most infants. Their weights together with their serum iron, total iron binding capacity, and serum ferritin were judged to be independent variables of iron status, whereas the hematologic variables were considered to be response variables indicative of iron status. The correlation coefficients among these variables, after excluding redundant variables and transforming to logarithms, were computed. Canonical correlation analysis was applied to the matrix of correlation coefficients to yield the linear function of the independent variables most highly correlated with a linear function of the response variables. The linear function of the response variables was found to be well approximated by the logarithm of the mean corpuscular haemoglobin, which was highly correlated with each of the independent variables.