As a diagnostic test for patients with suspected Parkinson's disease (PD), single photon emission computed tomography (SPECT) using [ 123 I]FP-CIT tracer has better sensitivity but is more expensive than regular clinical examination (CE). Our objective was to evaluate the clinical and economic impacts of different diagnostic strategies involving [ 123 I]FP-CIT SPECT. We developed a decision tree model to predict adequate treatment-month equivalents (ATME), costs, and incremental cost-effectiveness ratio (ICER) during a 12-month time horizon in patients with suspected PD referred to a specialized movement disorder outpatient clinic. In our costeffectiveness analysis, we adopted the perspective of the German health care system and used data from a German prospective health care utilization study (n ϭ 142) and published diagnostic studies. Compared strategies were CE only (EXAMϩ), SPECT only (SPECTϩ), SPECT following negative CE (SINGLEϩ), and SPECT following positive CE (DOUBLEϩ). Costs of SPECT amounted to €789 per investigation. Based on our model, expected costs (and ATME) were €946 (52.85 ATME) for EXAMϩ, €1352 (53.40 ATME) for DOUBLEϩ, €1731 (32.82 ATME) for SINGLEϩ, and €2003 (32.96 ATME) for SPECTϩ; performance of SPECT was induced in 0%, 54%, 56%, and 100% of the patients, respectively. DOUBLEϩ was more effective and less expensive than SINGLEϩ or SPECTϩ; thus these two do not offer reasonable choices. The ICER of DOUBLEϩ compared to EXAMϩ was €733 per ATME gained. In sensitivity analyses, the ICER of DOUBLEϩ versus EXAMϩ ranged from €63 to €2411 per ATME gained. Whether the diagnostic work-up of patients referred to a specialized movement disorder clinic with a high prevalence of PD should include [ 123 I]FP-CIT SPECT depends on patient preferences and the decision maker's willingness to pay for adequate early treatment. SPECT should be used as a confirmatory test before treatment initiation and limited to patients with a positive test result in the clinical examination. These results should be adjusted to the specific setting and individual patient preferences.