OBJECTIVES: To evaluate cost and cost-effectiveness of tiotropium monotherapy administered for 24 months (18 mcg die) in patients suffering from mild-to-moderate and severe chronic obstructive pulmonary disease (COPD). METHODS: A recent published study showed that tiotropium monotherapy enables a significant minimization of morbidity in two groups of patients corresponding to predicted FEV1 baseline values ≤ 50% (A) and > 50% (B). Clinical outcomes (days in hospital, visits in general ward, cycles of systemic steroids, cycles of antibiotics and maintenance therapy drugs) were evaluated from the Italian NHS perspective. In order to perform cost-effectiveness analysis, FEV1 value, available for each patient, was converted in SGRQ score using a published multivariate linear model; then utilities were obtained through the Ståhl equation. RESULTS: Results from comparison between 24 months of standard therapy and subsequent 24 months of tiotropium monotherapy show that hospitalization cost, which represents the driving treatment cost, drops from 74.1% to 67.3% (A) and from 64.5% to 31.6% (B) of the total cost; differently maintenance therapy cost increases but it is more than offset by the savings accruing from the shortening of hospitalization. Furthermore, cost-effectiveness results reveal a mean saving of 216 € (A) and 900 € (B) other than a mean gain of 0.07 QALY(A) and 0.03 QALY(B). Dominance of tiotropium calculated only with patients completing treatment course reveal that in almost 30% (A) and 37% (B) of subjects tiotropium strategy is dominant while only in 2% (A) and 7% (B) of cases are associated to costs increment and worsening on quality of life. CONCLUSIONS: These results suggest that adoption of tiotropium as unique treatment in selected mild-to-moderate and severe COPD patients yields significant costs savings and has a beneficial effect on evaluated quality of life.