OBJECTIVES: This study assessed the economic value of using SPECT-DaTSCAN (123I-FP-CIT) in comparison with current clinical judgement, in the diagnosis of patients with clinically uncertain Parkinsonism in Italy. METHODS: A cost-effectiveness analysis was based on a Markov model, comparing a cohort of patients following a diagnostic pathway including or excluding DaTSCAN, using a time horizon of 5 years. The model was populated with direct medical costs (drugs, tests, exams, hospital admissions, management of adverse events) associated with diagnosis and treatment, diagnostic accuracy (sensitivity: 97%, specificity: 100%), the underlying prevalence of diseases in the tested population (estimated to be 49%), rates of adverse events, therapy progression and death. Effectiveness was expressed as the (gain in) number of years of appropriate therapy per patient. Model input values were estimated using a double round Delphi panel performed with 12 Italian specialists. Diagnostic accuracy, adverse event rates and mortality rates were based on published studies. RESULTS: The current diagnostic pathway produced on average 2.3 ‘adequately treated years' (ATYs) per patient at an estimated cost of €8,893 to the healthcare system over 5 years. The DaTSCAN pathway generated on average 4.1 ATYs per patient at an estimated cost of €8,410. Use of DaTSCAN rather than current diagnostic practice generated an additional 1.8 ATYs at a cost saving of €482 per patient over 5 years. Discounting at 5%, the cost saving became €372 per patient over 5 years. If the use of DaTSCAN decreased other diagnostic work-up costs by €450 (estimated by clinical expert), cost savings became €932 (undiscounted) per patient tested. The result is sensitive to the proportion of patients tested. CONCLUSION: The analysis suggests that using DaTSCAN in patients with clinically uncertain Parkinsonism is an economically attractive intervention. Greater amounts of time on appropriate therapy are achieved at less cost to the healthcare system.