Tests of academic aptitudes and achievements taken by students in the Hawaii state system of primary and secondary education during the period 1967–1970 were linked to a file of birth records relating to children born in the state over the 19-year period 1948–1966. Estimates of the heritability and genetic correlation values of these traits were obtained. Explicit results are presented from analyses on test scores of 19,404 full sibs from 8,392 sibships. Consistent estimates were obtained from repeated tests on these same individuals as well as from a second independent sample of 7,859 full sibs from 3,465 sibships.