Background— The aim of the Köln (Cologne) Infarction Model is to examine the feasibility of obligatory treatment of ST-segment–elevation myocardial infarction (STEMI) by first-line percutaneous coronary intervention. Methods and Results— The study was performed in Cologne with >1 million citizens, 5 coronary intervention centers, and 11 primary care hospitals. Twelve-lead ECG was available for all emergency medical service (EMS) teams. Partners guaranteed direct transfer of STEMI patients to a catheterization laboratory. A total of 519 patients treated within KIM in 2006 were included in the study. Of these, 24% presented at a primary care hospital, 11% presented directly at a coronary intervention center, 5% were transferred by EMS to primary care hospitals, and 60% were directly transferred by EMS to a catheterization laboratory. In 91% of cases, the catheterization laboratory was notified of the patient’s arrival in advance. False-positive ECG diagnosis of STEMI by EMS accounted for 6%. Median treatment times were as follows: from the start of symptoms to first medical contact, 120 minutes; phone to balloon, 70 minutes; and door to balloon, 49 minutes. Of all patients, 93% underwent angiography; 409 patients were treated by coronary intervention, and 24 underwent emergency coronary artery bypass graft. Thrombolysis in Myocardial Infarction grade 3 flow was obtained in 89%. In the hospitals, deaths and new myocardial infarctions were observed in 12.1% and in 1.9% of all patients, respectively. Conclusion— The Cologne Infarction Model provides evidence for the feasibility of obligatory treatment of STEMI by primary coronary intervention in a metropolitan setting. Acceptance of treatment pathways allowed nearly all STEMI patients to undergo coronary angiography. ECG competence of EMS was excellent. Treatment times were within postulated limits. Results, including mortality, were within a high quality range.