OBJECTIVES: To evaluate costs and benefits of diagnosing patients of syncope with unknown aetiology with standard of care or with implanted loop recorders in Spain. METHODS: Syncope is a recurrent and unpredictable symptom. It accounts for 6% of hospitalisations and nearly a third of syncope cases remain of unknown etiology after the initial testing. We have evaluated the direct health care costs and diagnostic yield of a conventional diagnosis pathway and compared them with a strategy that includes a subcutaneous device for the diagnosis of syncope (Reveal DX®) in the Spanish context. An economic model was built to analyze the diagnosis yield of Reveal DX®, and costs of both diagnostic strategies. It was based on a clinical trial approach, the Eastbourne Syncope Assessment Study (Farwell, 2006). We used 2007 updated Spanish Cost data from the literature. RESULTS: Reveal DX with an ICER per additional diagnosis made of 2186€ (95% CI €1761-€5041) is cost effective in Spain. The ICER Confidence Interval (CI), was calculated with Probabilistic Sensitivity Analysis to account for the variability of medical resources, unit costs and diagnostic yield.  CONCLUSIONS: Introducing Reveal DX® in the diagnosis of syncope of unknown etiology in Spain is a cost effective strategy since it increases diagnostic yield at a reasonable incremental cost for the Spanish Health System.