Intravenous streptokinase (STK) was given in the field by a physician-staffed mobile intensive care ambulance to 13 patients. Patients waited 33 +/- 17 minutes to call the ambulance, arrival time was 5 +/- 3 minutes, and a further work-up time of 32 +/- 8 minutes elapsed. The average time from the onset of pain until administration of STK was 66.7 minutes. Patients were transferred to hospital without important side effects or complications. Eleven of 12 of the infarction-related arteries were patent on subsequent coronary angiography. Three patients had minor hematomas and two had microscopic hematuria. This pilot study shows that intravenous STK can be given with relative ease and safety at home by an experienced physician capable of treating any complications.