Endovascular thrombectomy is the standard treatment in selected patients with acute ischemic stroke and large vessel occlusion, but continuous improvement in angiographic and clinical outcome is still needed. Intra-arterial thrombolysis has been tested as a possible rescue tool in unsuccessful thrombectomy, or as an adjuvant therapy after the endovascular procedure, to pursue complete recanalization. Here we present a case series analysis of intra-arterial alteplase administration (5 mg bolus, repeated up to 15 mg if Thrombolysis in Cerebral Infarction (TICI) scale ≥2c is not achieved) in 15 consecutive anterior circulation stroke patients after unsuccessful thrombectomy, defined as TICI score ≤2b after at least 3 passes or if unsuitable for further endovascular attempts, with the aim of improving recanalization. An improvement of final TICI score was achieved in 10 of 15 patients (66.7%). TICI score ≥2c was achieved after 5 mg intra-arterial tissue plasminogen activator (iaTPA) in 4 patients, and after 10 mg iaTPA in 5 cases. Six of 15 patients received 15 mg iaTPA: 1 of 6 showed angiographical improvement. A major effect of intra-arterial alteplase was observed for distally migrated emboli. None of the patients experienced any symptomatic hemorrhagic transformation or other major bleeding. Our report shows, in a very small cohort, a high rate of final TICI score improvement, encouraging the development of randomized controlled trials of rescue intra-arterial thrombolysis in patients with suboptimal angiographic results after mechanical thrombectomy.