To replicate and extend Cramer's (1987) original cross-sectional study concerning the development of defense mechanisms, the Thematic Apperception Test responses of 148 students in Grades 2, 5, 8, 11, and college freshmen were collected and scored for denial, projection, and identification using Cramer's Defense Mechanisms Manual (1991). Our results supported the notion that the relative use of denial and projection decreases and identification increases as a function of grade level. The findings provide additional support for the psychoanalytic view (Freud, 1966) of an ontogenetic developmental line of defense.