BACKGROUND Early reperfusion therapy with primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) improves left ventricular function and reduces mortality. AIM To assess the time delay in treatment of patients with STEMI referred to a twenty-four-hour interventional centre located in the vicinity of the centre of Warsaw. METHODS We analysed 350 consecutive STEMI patients admitted to our Department between October 2005 and September 2006. The majority of the patients - 244 (69.7%), were admitted via hospitals without an interventional department. Sixty-two (17.7%) patients were transported directly by ambulance from home, 34 (9.7%) from a community health centre and 10 patients (2.9%) came by themselves from home or work. A detailed interview concerning the time of symptom onset was conducted in 342 patients (97.7%). RESULTS Sixty-two (18%) patients arrived at the interventional centre within the first 2 hours from symptom onset: 6 women (5.5% of all women in the study population) and 56 (24.1%) men (p <0.0001). Within the first 2 hours, 32 (13.1%) patients were admitted via another hospital and 20 (32.2%) directly by ambulance (p <0.001). During the first 7 days of hospitalisation the following patients died: 2 (3.2%) patients admitted within the first 2 hours via another hospital, 6 (3.4%) patients among 178 admitted between 2 and 6 hours after pain onset, 4 (8.3%) among 48 admitted between 6 and 12 hours and 8 (14.8%) among 54 patients with the pain duration over 12 hours (p <0.02). During the first 7 days of hospitalisation 8 (3.3%) patients admitted within the first 6 hours after pain onset died compared with 12 (11.8%) admitted later (p <0.003). CONCLUSIONS In the interventional centre located near the centre of Warsaw symptom-onset-to-door time was 120 minutes only in 18% of patients with STEMI. Almost 70% of patients underwent interhospital transfer for primary PCI. Prolongation of the time from onset of symptoms to successful PCI worsened prognosis. When transporting patients with acute coronary syndrome, efforts should be made to avoid district hospitals without a catheterisation laboratory. Direct transportation by ambulance or helicopter with educated staff equipped with ECG teletransmission data, which may substantially shorten time to treatment, should be preferred.