Background: Chronic Obstructive Pulmonary Disease (COPD) affects about 4.5% of the Italian population, representing one of most burdensome public health problems. Literature data report an annual health care expenditure ranging between € 1,300 and € 4,500 per patient, of which drug costs are a limited share. In 1998 the WHO started GOLD program in order to ameliorate COPD patient management. As a part of his program, periodically updated guidelines are produced with the aim of defining an efficient diagnostic-therapeutic pathway managed by a multidisciplinary team and based on the optimization of the use of drugs and diagnostic tests and the reduction of exposure to risk factors.Objective: to estimate the economic consequences of GOLD guidelines adoption in the Italian clinical practice.Methods: a decision analytic model capable of calculating the impact on the National Health Service budget of an ameliorated adherence to GOLD guidelines (GOLD GL strategy), basing on the needed variations in health care strategies on a defined patient cohort treated with the current approach (CURRENT strategy). The simulation runs on a cohort representing Italian COPD patients over 45 years who transit through 5 Markov health states (4 GOLD stages and death), according to patient characteristics (age, gender, FEV1), with a time horizon of 3 years. Stage-specific drug consumption of the CURRENT strategy is based on data of 3,113 patients collected by three Health Local Units involved in a larger clinical audit project. The consumption of other health resources, i.e. medical visits and inpatient care, is estimated based on a multicentre observational Italian study. The GOLD GL strategy includes spirometry-based staging on the totality of the simulated patients, the development of a therapeutic strategy including the redefinition of pharmacological therapy based on guideline recommendations and experts opinion, and variation of other health resources consumption based on observational data. Costs of health care resources are calculated based on published micro-costing analysis and current prices and tariffs.Results: the model estimates an adjunctive cost of about 19 million of Euros with the GOLD GL strategy, just for the the spirometry-based restaging of about 40% of the over 1 million and 250 thousand prevalent Italian COPD patients. Furthermore, in the first year of the analysis, the redefinition of the best clinical management strategy for all patients would cost about 100 million Euros, which are to be added to the more than 320 million Euros associated with adaptation of the GOLD stage specific pharmacological therapy, consisting mainly in a higher usage of long-acting beta agonist/corticosteroid combinations, only partially offset by the lower prescription of corticosteroid alone. Based on Italian observational data, the consumption of other health care resources with the GOLD GL strategy is reduced by about 44%, reflected in an estimated cost saving of more than 850 millions of Euros. For the first analysis year, the net cost saving associated with full GOLD guideline adoption is estimated equal to 410 millions of Euros; this value decreases by 11% and 21% respectively in the second and third years.Conclusion: our model estimates that the adoption of GOLD guidelines in the Italian clinical practice is associated to an average cost saving of about 300 Euros per patient/year.