In this longitudinal study, individual differences in security of attachment at 18 months and effective autonomous functioning at age 2 years were related to the dimensions of ego-control and ego-resiliency at age 4--5 years. The kindergarten or nursery school teachers of 26 children completed California Child Q-Sorts. The children were also given a short form of the Block's laboratory battery (Banta's curiosity box, level of aspiration, motor impulse control delay of gratification, the Shure and Spivack Preschool Interpersonal Problem-solving Test, and the Lowenfeld mosaics). Following the Blocks, composited ego-resiliency and ego-control scores were derived from each data set. Children earlier classified as securely attached were, as predicted, significantly higher on ego-resiliency on both laboratory and Q-sort composites. They were also higher than anxiously attached infants on 3 independent measures of curiosity. An independently composited index of competence from 2-year tool-using measures also correlated significantly with later resiliency, as did 2-year measures of mothers' support and quality of assistance. The data provide initial links between the infant's quality of attachment, the toddler's effectiveness in a problem-solving situation, and competence during the preschool years.