Background: Pharmaceutical manufacturer coupons are a rapidly growing promotional activity intended to encourage initiation and continuing use of brand-name medications, but little is known about impacts on medication adherence and expenditures. Ob jecti ve: To understand which patients use manufacturer coupons and the impact of coupons on brand-name statin (atorvastatin and rosuvastatin) use and expenditures 1 year after initiation of statin therapy. Methods: Using commercially available claims data spanning 3 years and representing 340,350 patients, we compared demographics, statin use, and expenditures of patients initiating generic statins, brand-name statins without manufacturer coupons, and brand-name statins with manufacturer coupons. Differences in user groups were tested using chi-squared statistics and Wilcoxon-Mann-Whitney tests. Main outcome measures included statin fills, adherence, and expenditures, including patient out-of-pocket, payer, and total costs. Resu lts: With the exception of population density, there were no significant demographic differences between new to therapy brand-name statin users filling prescriptions with and without coupons. New to therapy patients using generics were younger and lived in less populated areas compared with new to therapy brand-name statin noncoupon users. The number of statin fills in the 12 months following initiation was highest for coupon users, slightly lower for patients initiating generic statins, and lowest for noncoupon users (7.1 vs. 6.3 vs. 5.8; P < 0.001), with corresponding medication adherence rates (61.1% vs. 60.1% vs. 53.8%; P < 0.001). Coupon users had higher total statin prescription costs than generic initiators and noncoupon users ($798 vs. $92 vs. $678; P < 0.001), and higher precoupon out-of-pocket costs ($339 vs. $53 vs. $169; P < 0.001). Health plan costs for statins excluding rebates were lower for coupon users than noncoupon users ($460 vs. $508; P < 0.001) but were much higher compared with generic statin initiators ($460 vs. $39; P < 0.001). Conclusi ons: Brand-name statin initiators using coupons have higher adherence than patients initiating generic statins or brand-name statins without coupons. While the differences in adherence were statistically significant, they may not be clinically significant. Higher adherence among coupon users appears to occur at the expense of higher out-of-pocket and total statin expenditures.