We aimed to evaluate platelet activation and fibrinolyis in acute atherosclerotic ischemic stroke patients to clarify the relationship between them. Plasma P-selectin antigen, tissue plasminogen activator (tPA) antigen and activity, and plasminogen activator inhibitor-1 (PAI-1) activity were determined in 60 acute atherosclerotic stroke patients and matched control subjects. All patients were examined within 72 h after stroke onset. The levels of P-selectin, tPA antigen, and PAI-1 activity were all significantly higher in stroke patients compared with controls (all p < 0.0001); the level of tPA activity was significantly lower in patients than that in controls (p < 0.0001). These markers did not change much at different time points within 72 h. In stroke group, P-selectin concentration was highly correlated to PAI-1 activity (r = 0.8433, p < 0.001), but not to tPA antigen (r = -0.1752, p > 0.05), and tPA activity (r = 0.2465, p>0.05), which was further confirmed in the multiple linear regression analysis (F = 47.052, p < 0.0001). Our results indicate increased platelet activation and decreased fibrinolysis in patients with acute atherosclerotic ischemic stroke. Increased platelet activation may be correlated with decreased fibrinolysis.