The prevalence of prasugrel contraindications and specific conditions requiring precaution for its use in a real world acute coronary syndrome (ACS) population is not known. We performed a prospective descriptive study in 1016 consecutive moderate to high risk ACS patients. In 646 patients (63.6%) subjected to percutaneous coronary intervention, analysis of absolute contraindications (history of stroke/transient ischemic attack or active bleeding), relative contraindications and specific conditions (age ≥ 75 years and/or weight < 60 kg) for prasugrel theoretical administration was performed. In 242 (37.5%) patients there was at least one absolute or relative contraindication or specific condition requiring attention for its use. Overall, 23.1% of patients in our cohort had a prior stroke/transient ischemic attack and/or specific condition to be considered for prasugrel administration. Specifically, the prevalence of stroke/TIA was 3.6%, the prevalence of patients ≥75 years 20% and the prevalence of patients weighing <60 kg 2.2%. Among patients ≥75 years old, 63 (9.8%) had diabetes mellitus or previous myocardial infarction, consisting a high risk subgroup that might benefit from prasugrel administration. In a real world ACS population a relatively high proportion of patients have a potential contraindication for prasugrel administration or necessitate special attention for its use.