Purpose Although hydatid liver cyst (HLC) is a benign disease, treatment is recommended to avoid life-threatening complications. There are several treatment options for HLC: “wait-and-watch,” medical or surgical or percutaneous treatment. The purpose of this study was to assess the long-term effectiveness of an alternative of the traditional percutaneous PAIR procedure, called double percutaneous aspiration and ethanol injection (D-PAI). Materials and Methods This prospective, non-randomized study was conducted from 1988 to 2019 using DPAI procedure characterized by no reaspiration of the ethanol injected to replace the aspirated fluid and repetition of the procedure after 3–7 days. Results Two hundred and three patients with 290 HLCs underwent D-PAI. Two hundred and two HLC (160 patients) were univesicular cysts and 88 (43 patient) were multivesicular. Seventeen patients underwent one D-PAI session, 15 patients two sessions, and 18 up to four sessions. The follow-up ranged 0.9–21 years (median 6.5 years). On ultrasound, 188 cysts (64.8%) disappeared; 57 cysts (19.7%) became solid (inactive) and 45 (15.5%) showed a small inactive residual component. Parasitologic cure was very high. The overall response to D-PAI was higher than 90% considering also the procedures carried out after the first D-PAI at the time of recurrence. One patient died for anaphylactic shock. The hospital stay ranged 1–3 days. Smaller cysts (< 5 cm) healed sooner than larger cysts ( p  < 0.001). Conclusions Long-term analysis showed that D-PAI is a safe and effective option in percutaneous treatment of viable HLC, except for CE2/CE3b in which the recurrences can be observed. This inexpensive and simple procedure can be applied everywhere and especially in developing countries.