OBJECTIVES: STEMI patients (pts) presenting <12h since onset of symptoms should receive reperfusion therapy, which results in important mortality reduction. However, critical presentation timing is not the only factor that influences treatment choice for STEMI pts. In this study we assess the scale at which clinical guidelines are followed in the treatment of STEMI patients presenting within the timeframe of reperfusion therapy.Methods: This was a retrospective patient diary study using the IMS Health Acute Cardiovascular Analyzer.  The study was conducted in 264 hospitals with Cath-Lab facilities in France, Germany, Italy, Spain and UK. They treated a total of 2553 patients diagnosed with STEMI, during the period of August 2006 and April 2007, with a mean of 10 patients per hospital. Hospitals were selected to be representative by geographic regions, size and facilities in each country. We analysed the data to determine factors associated with patients not receiving reperfusion therapy.Results: We found 2333 (91%) pts were admitted within 12 hours of onset of symptoms, where 49% had primary PCI, 16% received thrombolytics, 15% received thrombolytics and PCI, 8% had PCI outside the 12 hours reperfusion window, 9% didn’t receive PCI neither thrombolytics, 2 % had CABG: We report data from 393 patients who didn’t receive reperfusion therapy and accounts for patients not receiving primary PCI or thrombolytics: 66% had dyslipidaemia, 63% hypertension, 37% CHF, 30% diabetes, 19% age >80, 12% stable angina and 11% with PAD.  Also, it was noted that 40% of these patients experienced delay in-hospital diagnosis, and thus haven’t received reperfusion therapy within the 12 hours window, 10% were contraindicated to thrombolytics, and 39% were scheduled to receive revascularisation. In-hospital mortality accounted for 14% of the total untreated population. Conclusion: This study concludes that 17% of STEMI patients admitted to Cath Lab hospitals within 12 hours of onset of symptoms in Europe don’t receive reperfusion therapy even when catheralization facilities are available.