Releasable vascular plasminogen activator was measured in 28 patients (14 males and 14 females) with a history of thrombotic strokes documented by computed tomographic scanning. Levels were compared with those in a control population of 126 healthy subjects with no history of thromboembolic disease. The patient population tended to have higher levels of activator than the control population, 0.53 Committee on Thrombolytic Agents (CTA) units/ml of plasma for patients versus 0.21 CTA units/ml for control subjects; however, there was a wide distribution of values, as reported in all previous populations. Since plasminogen activator levels distribute in a non-Gaussian manner, patient values and control values were stratified into deciles. By this approach, the distribution among the patient was not significantly different from that among the control subjects except in females, who demonstrated skewing to higher deciles (p = 0.019). It is concluded that thrombotic strokes are not associated with low levels of releasable vascular plasminogen activator, and in fact, these patients may present with levels considerably above the mean for normal subjects.