OBJECTIVE: Evaluate whether use of salmeterol increases the risk in an asthma-related hospitalization or emergency care. METHODS: Data for this study were extracted from the MEDSTAT pharmacy and medical claims databases between January 1, 2000 and December 31, 2001. A nested case-control study design was employed to evaluate the associations of interest. A cohort representing asthma patients was identified in 2000. The hospitalized cases were then identified as those with the first-time asthma-related hospitalization in 2001, and matched to select controls from the study cohort by age (± 5 years of age), sex, and number of ambulatory visits for asthma (5:1 control to case ratio). A similar selection process was used for the asthma-related emergency department (ED) visit outcome. The use of salmeterol was evaluated during the one-year period before an index date for both cases and controls. Conditional multiple logistic regressions were used to model the association of interest. RESULTS: A total of 35,312 subjects were eligible to be the study cohort. In addition, 284 and 640 subjects were identified as the hospitalized and ED cases, respectively. Current use of salmeterol was associated with a 48 percent decrease in the risk of an asthma-related hospitalization (OR = 0.52; 95% CI = 0.30 to 0.90) and a 30 percent reduction in the risk of an asthma-related ED visit (OR = 0.697; p = 0.048). The protective effect of salmeterol did not exist for those with recent or past use of salmeterol. Conversely, use of seven or more canisters of salmeterol had a decreased risk in the outcomes of interest (hospitalization: OR = 0.45; p <0.001; ED visit: OR = 0.49; p <0.001). CONCLUSIONS: Salmeterol decreases the risk of health care utilization if salmeterol is currently used or salmeterol is used for seven or more canisters during a one-year period.