This study investigated differences in ego functions of borderline and narcissistic personality disorders through examining responses to Rorschach structural and content variables. Reality testing, thought process, affective regulation, impulse control, and the defenses of splitting and grandiosity were examined from Rorschach protocols of 50 borderlines and 26 narcissists. The borderlines produced greater distortion in reality testing, p less than .05; the narcissists produced more insidious thought process disturbance, p less than .05; and higher functioning groups demonstrated greater control of impulses, p less than .05. Borderlines in this sample demonstrated more affective constriction than the narcissists and used more splitting, p less than .05; narcissists used more grandiosity, p less than .05. Implications of this study are (a) ego functions mature inconsistently, (b) affective responsivity influences ego disorganization, and (c) level of functioning and IQ are related to the production of Rorschach variables.