Routine self-monitoring of blood glucose is a low-value practice that provides limited benefit for patients with non-insulin-treated type 2 diabetes mellitus. We estimated the costs of Rethink the Strip (RTS), a multistrategy approach to the de-implementation of self-monitoring of blood glucose in primary care. RTS was conducted among 20 primary care clinics in North Carolina. We estimated the non-site-based and site-based costs of the 5 RTS strategies (practice facilitation, audit and feedback, provider champions, educational meetings, and educational materials) from the analytic perspective of an integrated health care system for 12 and 27-month time horizons. Material costs were tracked through project records, and personnel costs were assessed using activity-based costing. We used nationally based wage estimates. Total RTS costs equaled $68,941 for 12 months. Specifically, non-site-based costs comprised $16,560. Most non-site-based costs ($11,822) were from the foundational programming and coding updates to the electronic health record data to develop the audit and feedback reports. The non-site-based costs of educational meetings, practice facilitation, and educational materials were substantially lower, ranging between ~$400 and $1000. Total 12-month site-based costs equaled $2569 for a single clinic (or $52,381 for 20 clinics). Educational meetings were the most expensive strategy, averaging $1401 per clinic. The site-based costs for the 4 other implementation strategies were markedly lower, ranging between $51 for educational materials and $555 for practice facilitation per clinic. This study provides detailed cost information for implementation strategies used to support evidence-based programs in primary care clinics.