The central tenet of Gottfredson and Hirschi's self-control theory is that antisocial behavior is caused by stable between-individual differences in self-control. They also argue that after early childhood, interventions aimed at reducing antisocial behavior will be unsuccessful, as one's level of self-control is resilient to such efforts. This research tested the stability and resiliency hypotheses using a two-wave panel design in a sample of incarcerated offenders. The results indicated that self-control was not stable during a short period of time but that self-control was resilient to participation in a treatment-oriented boot-camp program. (Contains 4 tables and 7 notes.)