The data were obtained from the Montreal Two-Sample Longitudinal Study, which includes two samples of Caucasian French-speaking men first recruited in the mid-1970's. The current study used the subsample of boys adjudicated during their adolescence, which included all the adjudicated males (n=470) referred to the Montreal-area Juvenile Court in 1974-75. These adolescents were sentenced to probation or, in most cases, a residential placement. At the first wave of data collection (spring 1974 to spring 1975), interviewers administered self-report questionnaires and questions from an interview protocol based on an integrative multilayered theory of delinquent and antisocial behavior. Two years later, the participants completed the same interview. During adulthood, they were interviewed at an average age of 31.7 and again in 1998-99 at an average age of 40.8. At each wave of data collection, the participants were asked about numerous aspects of their lives, including their behaviors, their family, their relationships with peers, their routine activities, their beliefs and values, and their personality. Complete personality data were available for 122 of the participants. In addition to personality traits, attention was given to antisocial behavior, including criminality, substance use, behavioral problems, work problems, and conjugal problems. Cluster analyses were performed on measures of disinhibition, negative emotionality, and extraversion. Four developmental types of personality were identified. One was characterized by average scores on the three traits in adolescence that decreased linearly until midlife (39 percent). A second personality type displayed very high scores in disinhibition and negative emotionality in adolescence that decreased rapidly during early adulthood (24 percent). The third type was characterized by very high scores in disinhibition and negative emotionality that remained stable until midlife, while extraversion was average during adolescence and then decreased rapidly until midlife (17 percent). The fourth type was characterized by high scores on disinhibition and negative emotionality in adolescence that was followed by cycles of decreases and increases until midlife (20 percent). These four developmental types of personality were apparently related to known antisocial behavioral trajectories. The authors discuss some implications of these findings for the developmental-typological perspective of personality, and the strengths and limitations of the study are noted. 2 tables, 2 figures, and 64 references