Abstract Aims The objective of the study is to determine the demographics and the in-hospital outcome of diabetic and non-diabetic patients treated with percutaneous coronary interventions (PCI) in Europe, to report the type of equipment and technology used for PCI procedures in diabetics and to clarify whether the treatment of diabetic patients complies with current European Society of Cardiology (ESC) guidelines. Methods and results A total of 14,458 patients treated with PCI were enrolled from 29 member countries of the ESC between June 2005 and January 2006. Data were collected on patient characteristics and treatment, using new Cardiology Audit and Registration Data standards. In total, 3603 patients (24.9%) were diabetic. Diabetics were older, more often female and had a higher body mass index than non-diabetics. Diabetics had higher rates of hypercholesterolaemia and hypertension, while current smokers were more frequent in the non-diabetics. Diabetics also had significantly higher rates of previous cardiovascular events. Clopidogrel was administered only in 48.1% of diabetic patients before PCI, while IIb/IIIa inhibitors were 22.9% during PCI. At discharge, there was a major adjustment of treatment with increases in the use of Beta-blocker (80.4%), angiotensin converting enzyme inhibitor (ACEI, 71.3%) and statins (89.8%) compared with on admission (Beta-blocker 60.9%, ACEI 55.0%, statin 63.1%). In-hospital mortality was higher in diabetics (1.8% vs 1.2%) although the in-hospital MACCE rate was not significantly different (3.6% vs. 3.0%, p = 0.09). Conclusions Diabetic patients treated with PCI were older with more comorbidity. According to ESC guideline, the under-usage of clopidogrel, GP IIb/IIIa inhibitors should be improved. PCI is now taken as a good opportunity to adjust the use of appropriate medication.