The study examined the contribution of reinforcement sensitivity to childhood personality at three levels of the hierarchical structure, mid-level traits, the Big Five and two higher-order factors, and the moderating role of sex and age in a sample of 3-18-year-olds. The canonical correlation analyses indicated that reinforcement sensitivity and personality have more than 50% of common variance; reward and punishment sensitivities had opposing effects and were linked to both higher-order factors, Extraversion and Agreeableness, and lower-order traits Sociability and Shyness. There were no sex differences in the effects of reinforcement sensitivity, the negative effect of reward sensitivity on Alpha domain in school age was higher than in adolescence, whereas the negative effect of punishment sensitivity on Beta domain decreased from age 3-4 years to age 17-18 years. (Contains 4 tables and 1 figure.)