By the aid of the radial immunodiffusion method immunoglobulin G and albumin concentration were determined in cerebrospinal fluid of 58 boys and 47 girls (ages 1 month - 14 years). On the basis of clinical criterions these children were considered to be "healthy". The total number of examined children was 1200. RESULTS The sex-specific investigation of the 1 month-2 years and the 2-14 years old children showed no statistical significant differences. But the agespecific investigation revealed that the immunoglobulin G concentration in the cerebrospinal fluid of the older girls was statistically significant higher as compared to the younger girls and that the albumin concentration in the cerebrospinal fluid of the older boys was statistically significant lower than in the younger boys. The immunoglobulin G/albumin quotient was statistically significant higher in the group of older girls as compared to the group of younger girls.