Subjects indicated the age at which they first committed nine acts taken from a general behavioral deviance scale (minor offenses). They were also asked to report the number of times in the last year they had committed each act. Data were also obtained on individual functioning, school functioning, family functioning, and demographic characteristics. Subjects reporting the onset of delinquency at an early age were more likely to report more delinquent behavior, to be adjudicated, and to show different delinquency patterns. Late onset of delinquency was more suggestive of transient and minor delinquency. Age of onset of delinquency was reliably differentiated by a combination of individual, school, family, and demographic variables. 5 tables, 2 figures, and 32 references.