BACKGROUND: 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors have significantly improved outcomes in coronary artery disease. They have anti-inflammatory and cholesterol-lowering effects. Statins alter the production of T(H)1 cytokines and thus promote a T(H)2 response. This immune alteration would promote allergic diseases such as asthma. OBJECTIVE: To ascertain whether statin use adversely affects the clinical course of asthma. METHODS: We retrospectively reviewed 759 medical records of consecutive patients with asthma to identify patients with extrinsic asthma who had at least 4 physician visits over 1 year. We compared patients who started receiving statins after their initial asthma evaluation with patients who never received statins. Baseline characteristics; change in forced expiratory volume in 1 second from baseline at 3, 6, 12, and 24 months; and a need for increases in medication and acute asthma visits were compared between the statin and control groups. RESULTS: We identified 24 patients who started statin therapy and 26 control patients. There was a statistically significant 3% to 5% median worsening of forced expiratory volume in 1 second at all time points for the statin group compared with the controls. At 6 months, more patients in the statin group needed increased maintenance medication (16 [67%] vs 7 [27%]; P = .005), used albuterol more frequently (18 [75%] vs 3 [12%]; P < .001), had more nocturnal awakenings (8 [33%] vs 0 [0%]; P < .001), and were seen more frequently at office visits for acute asthma (9 [38%] vs 1 [4%]; P = .003). CONCLUSIONS: This preliminary study demonstrated that patients with asthma who received statins had a worse clinical course than controls. Given the prevalence of both statin use and asthma, further research is needed.