OBJECTIVE: To evaluate economic costs from the health system perspective of an electronic health record-based clinical decision support (CDS) tool, TeenBP, designed to assist in the recognition and management of hypertension in youth. METHODS: Twenty primary care clinics within an integrated health system were randomized to the TeenBP CDS or usual care (UC), with patient enrollment from 4/15/14 to 4/14/16. The 12-month change in standardized medical care costs for insured patients aged 10 to 17 years without prior hypertension were calculated for each study arm. The primary analysis compared patients with ≥1 visit with blood pressure (BP) ≥95th percentile (isolated hypertensive BP), and secondary analyses compared patients with ≥3 visits within one year with BP ≥95th percentile (incident hypertension). Generalized estimating equation models estimated the difference-in-differences in costs between groups over time. RESULTS: Among 925 insured patients with an isolated hypertensive BP, the pre-to-post change in overall costs averaged $22 more for TeenBP CDS versus UC patients over 12 months, but this difference was not statistically significant (P = .723). Among 159 insured patients with incident hypertension, the pre-to-post change in overall costs over 12 months was higher by $227 per person on average for TeenBP CDS versus UC patients, but this difference also was not statistically significant (P = .313). CONCLUSIONS: The TeenBP CDS intervention was previously found to significantly improve identification and management of hypertensive BP in youth, and in this study, we find that this tool did not significantly increase care costs in its first 12 months of clinical use.