BACKGROUND Intravenous tissue plasminogen activator (IV tPA) was shown to be an effective treatment for acute ischemic stroke (AIS). According to stroke guidelines, there is no need to wait for the complete blood count (CBC) and coagulation test results before application of IV alteplase if there is no suspected coagulation disorder. In this study, a patient with AIS and thrombotic thrombocytopenic purpura (TTP) symptoms during thrombolytic treatment was presented. METHODS A 33-year-old male patient was admitted at the 2.5th hour of AIS symptoms onset with right hemiparesis and sensorimotor aphasia. Cranial computed tomography (CT) and diffusion magnetic resonance imaging did not reveal any abnormality. In his medical history, the patient did not have any contraindication for thrombolytic treatment. To avoid delays to thrombolytic therapy, blood samples were taken, and after that, IV bolus alteplase treatment was applied. During maintenance treatment, agitation and vomiting developed. The result of blood samples showed less than 26,000 mm3 platelet count and maintenance therapy was stopped. In control cranial CT, there was no hemorrhage. In the laboratory examination; anemia, low platelet count; increased indirect bilirubin, lactate dehydrogenase (LDH) levels were found, and fever was 38.4°C. Schistocytes were observed in peripheral blood smear and the patient was diagnosed as TTP. CONCLUSIONS Stroke guidelines recommend not to wait for the results of CBC and coagulation tests before IV tPA treatment in patients who do not have any history of coagulopathy disorder. If possible, before applying IV tPA we may wait for the results of coagulation and CBC tests, keeping in mind the diseaes with high mortality such as TTP.