This paper examines the introduction of premiums into the SCHIP program in Kentucky. Kentucky introduced a $20 monthly premium for SCHIP coverage for children with family incomes between 151% and 200% of the federal poverty level in December 2003. Administrative data between 2001 and 2004 is used to estimate a Cox proportional hazard model that predicts enrollment duration in this premium-paying category. The results suggest that a premium reduces the length of enrollment and that the effect is much stronger in the first two months after the introduction of the premium. Similar results are not found for the non-premium category.