Policymakers are concerned about disenrollment from the State Children's Health Insurance Program (SCHIP). We describe disenrollment in Florida, Kansas, New York, and Oregon and assess the links between disenrollment and States' SCHIP policies. We found that SCHIP is used on a long-term basis (at least 2 years) for a significant group of new enrollees and as temporary coverage (fewer than 12 months) for many others. Recertification generates large disenrollments (about one-half of children still enrolled at the time), but as many as 25 percent return within 2 months. The increased disenrollment rate at recertification is completely eliminated by a policy of passive re-enrollment.