High school and college students (N=321) completed the Mini Markers Five Factors Personality Scale (MMFFPS) and items assessing recent substance use, in order to permit an assessment of the relationship between five basic personality factors and reported use of cigarette, alcohol, and marijuana. A 2 x 2 MANOVA (personality factors; low and high; sex; male and female) on three types of self-reported substance use (cigarette, alcohol, and marijuana) was performed for each of the five personality factors assessed by the MMFFPS (openness, conscientiousness, extraversion, agreeableness, and neuroticism). A significant extraversion main effect was found for alcohol and marijuana use, and a significant conscientiousness main effect emerged on the alcohol use measure. A significant sex by conscientiousness interaction was obtained. No main effect emerged for sex on any of the three substance use measures. (Contains 20 references and 2 tables.) (Author)