There is ongoing debate regarding the relationship between early tobacco, alcohol and cannabis use and later cocaine abuse. We utilised data from two Irish national general population surveys. Of the 1,897 young adult participants, the prevalence of lifetime use was as follows: tobacco 62%, alcohol 96%, cannabis 31% and cocaine 7.0%. Logistic regression analysis indicated that being single, earlier age of first alcohol use, and history of cannabis use were significant independent predictors of lifetime use of cocaine. The substance use route to cocaine use in this Irish sample is quite typical of that seen internationally. Those who commence alcohol use in the early teenage years are more likely to use cocaine subsequently, even after controlling for early onset cannabis use and other socio-demographic characteristics. This suggests that policies which delay age of first drinking may possibly also curtail cocaine use.