Thrombolysis is now generally accepted as the initial treatment for patients with acute myocardial infarction (AMI). The extent to which this therapy is implemented in daily practice and the reasons for exclusion from thrombolytic therapy among 413 consecutive patients with AMI hospitalized in 18 coronary care units in Israel during a 1-month survey were prospectively investigated. Thrombolytic therapy administered to 145 patients (35%) was given to 38% of men versus 29% of women (p = not significant), to 38% of patients less than 75 years old compared with 18% of the very elderly (p less than 0.005), and more often to patients with a first or anterior AMI (40 and 48%) than to counterparts with recurrent or inferior AMI (23 and 31%, respectively, p less than 0.005 for both). The 2 most frequent reasons for excluding patients from thrombolysis were late arrivals to coronary care units (33%) and lack of ST elevation on the admission electrocardiogram (28%). Hospital mortality was 6% in the thrombolytic group versus 20% in patients found ineligible for thrombolysis. The significance of this difference is not clear as treatment was not randomized.