Thrombolytic therapy (TLT) is an effective treatment for ischemic stroke (IS). Three fibrinolytic agents are currently registered in the Russian Federation for the treatment of IS, including tenecteplase, which has demonstrated high efficacy and safety in several randomized controlled trials. We present three clinical case reports of patients with IS who, for the first time in the Russian Federation, underwent TLT with the domestically produced biosimilar of tenecteplase, Nektelisa. In all three patients with IS, we observed significant regression of neurological deficits after administration of tenecteplase within the first hour after TLT. The dose was adjusted according to the instructions for use, taking into account the patient’s body weight. In all three cases, the same neuroimaging method was used 24 hours after TLT as upon admission. No increase in the ischemic area was observed in any of the patients after 24 hours. In one case, a minor, clinically asymptomatic subarachnoid hemorrhage was detected, accompanied by rapid and complete recanalization of the occluded artery within the first 30 minutes after drug administration. In all three cases, we did not observe any other extracerebral hemorrhagic events. All patients were admitted with significant impairment of neurological functions and were discharged with mild or no significant impairment.