This paper uses data from the Rochester Youth Development Study, an ongoing panel study of urban youth, to examine the phenomenon of illegal gun carrying among young males. The analysis assesses the magnitude of gun carrying among these subjects and considers the consistency in carrying over the life course of the subjects from about fifteen years of age until about age twenty. It also examines the correlates of gun carrying. Depending upon their age, between 6% and 10% of subjects carry hidden guns at a given point in time, but carrying is rather sporadic. Carrying hidden guns is associated with high rates of many types of delinquency. Peer protection gun ownership, drug selling, and gang membership are the primary correlates of illegal gun carrying.