While there is a general consensus that temperament forms the enduring, biologically based foundation of personality and that this biological basis should imply some continuity within the individual across time, there is a limited literature exploring linkages between these areas. The purpose of this article was to provide an initial assessment of the relation between a two-factor model of temperament in early/middle childhood and the five-factor model of personality in late adolescence/young adulthood. Data were gathered from 115 children who had participated in a longitudinal study of early/middle childhood and who provided follow-up data 15 years later. Significant linkages were found between the two time periods. At the facet level, temperament in early and middle childhood accounted for an average of 32% of the variance in personality in late adolescence/early young adulthood. At the domain level, temperament accounted for an average of 34% of the variance.