Continuity of care during health care transition is critical. We sought to evaluate electronic medical record clinic attendance data to examine this outcome. We identified 1623 patients (ages 18-27 years) with 1 of 6 childhood-onset chronic conditions and tracked clinic utilization from January 2002 to July 2016. Patients were classified as active in pediatric care; lost from pediatric care; successfully transferred; or lost from adult care. Using random effects logistic regression, we compared the number of days between last pediatric and first adult visit to each clinic's self-reported transitional care quality score. In this cohort, >44% remained active in care at the end of the study. Clinics with higher proportions of successfully transferred patients had lower median numbers of days between last pediatric and first adult visit and higher transitional care quality scores. Characterizing utilization patterns with electronic medical record data allows health systems to track transitional care outcomes and target improvement efforts.