Percutaneous ethanol injection (PEI), as the first minimally invasive ablation method, has now been in use for more than 20 years. Its main indication is the treatment of small hepatocellular carcinomas superimposed on liver cirrhosis. PEI is highly effective for small tumors (<3 cm) with a complete response in 80% of patients. The efficacy for larger tumors (3-5 cm) is lower, with a complete response in 50%. To increase the effect in larger tumors some special techniques have been developed: single session therapy in general anesthesia, "multiple needles insertion", injection in the feeding artery. PEI is a well tolerated therapy, with a very low complication rate. Recurrences, either local or distant, may occur after PEI and can be treated with new sessions. Although it is still considered the standard percutaneous technique in the treatment of hepatocellular carcinoma, its place is challenged by the new thermal ablative percutaneous techniques, especially radiofrequency ablation.