Trends in the incidence of childhood cancer in Connecticut are reported and analyzed for the period 1935-1979 by 5-year age groups (0-4,5-9,lO-14,15-I9 years), using a log linear model method. A threefold increase (P < .001) in the incidence of ALL in males 0-4 years of age was observed, with significant increases of smaller magnitude seen in males aged 5-9 and 15-19 and females aged 0-4 and 5-9. The incidence of central nervous system cancers also increased in several age groups for both sexes with the largest increase seen in males 0-4 years old. Significant increases in incidence of large magnitude were also observed