Background: Thermal ablative techniques have gained increasing popularity as safe and effective options for patients with unresectable HCC. Microwave ablation has emerged as a relatively new technique with the promise of larger and faster ablation.Aim of the work: To evaluate percutaneous microwave ablation in treatment of large hepatocellular carcinoma (HCC) tumors (5-7cm) and to assess its effect on local tumor progression, prognostic outcomes and patient’s survival. Patients and Methods: Under ultrasound guidance 26 patients proved by triphasic CT to have HCC with a lesion diameter > 5cm to < 7 cm, were treated with a microwave generator through a percutaneous approach. Contrast-enhanced CT scan was carried out one, three and six months after treatment to assess efficacy. Local and distal tumor control and complications were analyzed.Results: Complete ablation was achieved in (19/ 26; 73.1%) of the lesions. Recurrence was recorded in 5 treated lesions (19.2%). De novo lesions were recorded in 6 patients (23.1%), with a mean survival of 21.5 months. No procedure related deaths, or major complications occurred.Conclusion: Percutaneous MWA is safe and effective for treating large HCC tumors. The local tumor control and survival are acceptable.