This paper reports the results of an ongoing study of individuals' ego control and ego resiliency. The study began with 130 subjects in 1969 when the subjects were in nursery school. At the most recent assessment, 104 participants still remained. Ego control is defined as the degree and kind of control individuals exert over their impulses, and ego resiliency as individuals' ability to modify their characteristic level of ego-control. An ego-resilient person tends to be resourceful and adaptive when confronted by new situations. An individual who is not ego-resilient tends to become inflexible when confronted by new situations, and is slow to recoup after stress. The study assessed individuals' ego control and resiliency when the subjects were 3, 4, 5, 7, 11, 14, 18, and 23 years old, by means of experimental measures, interactional procedures, self-evaluations, creativity tests, and clinical interviews. Results indicated a consistency in ego resilience across time for boys and a consistency in ego resilience during early childhood and adolescence, but not between these two periods, for girls. Results also indicated a consistency in ego control for both boys and girls. (ME)