This paper examines the relationships between age at first exposure to alcohol and four measures of drinking behaviour (frequency of drinking, typical and most amount consumed, alcohol-related problems) at age 15 years in a birth cohort of New Zealand children. There were small but consistent correlations (r = -0.10 to -0.16) between self-reported age at first exposure to alcohol and the four measures of alcohol consumption. These associations remained statistically significant (p < 0.05) after control for a wide range of potentially confounding covariates including measures of family socio-demographic background, parental alcohol use and attitudes to alcohol use and early childhood behaviour. After control for these factors, children who had been introduced to alcohol before the age of 6 years were 1.9 to 2.4 times more likely to report frequent, heavy or problem drinking at age 15 years than children who did not drink alcohol before the age of 13. It is concluded that young people reared in home environments that have permissive attitudes to alcohol use and who are introduced to alcohol at an earlier age may be more vulnerable to alcohol-related problems in adolescence.