- Background and objective Previous studies had demonstrated association between Tiotropium therapy (once-daily inhaled anticholinergic) and reductions of exacerbations, improvements in dyspnoea and quality of life in chronic obstructive pulmonary disease (COPD) patients. Little is known about the influence of adherence to Tiotropium on health-care utilization. Our objective was to examine whether adherence to Tiotropium is associated with decreased health-care utilization. Methods A computerized medical database was used to identify patients with COPD registered in an academic pulmonology institute who began therapy of Tiotropium 18 mg between 2008 and 2011 (n = 193). Adherence was assessed by calculating the proportion of days covered and defined as coverage of at least 80% of the follow-up period. Adherence to long-acting beta-agonists and/or inhaled corticosteroids (LABA and/or ICS) and health-care utilization were analysed 1 year before and 2 years after initiation of Tiotropium. A multivariate regression model was applied to examine determinants of change in health-care utilization. Results The median age of study population was 67 (80% male). Forty-one per cent of study population (n = 79) adhered to Tiotropium. Hospitalization costs decreased 1 year following treatment initiation only among adherent patient when their adherence to LABA and/or ICS improved (β = −463.6, P = 0.033). This cost did not change significantly in the consecutive second year (β = 206.3, P = 0.583). Conclusions Adherence to Tiotropium was associated with decreased hospitalizations only among patients who improved their adherence to LABA and/or ICS as well. Exploring reasons for high non-adherence and ways to improve adherence may optimize utilization of the scarce hospital resources.