The authors report their experience with ultrasound (US)-guided percutaneous treatment of hydatid abdominal cysts (mainly hepatic). From November 1987 to January 1996 in Italy and in Kenya 231 cysts in 163 patients were treated with a technique called PAIR (puncture, aspiration, injection, re-aspiration), using 95% ethanol as a scolecide agent according to a routine protocol. In Kakuma, Turkana (Kenya) 141 cysts in 85 patients were treated with a simplified protocol and a portable US machine. No anaphylactic shock or peritoneal dissemination was observed. One failure was observed due to the proximity of the parasitic cyst to the gallbladder, resulting in a fistula between the two cavities; this complication was resolved by surgery. A few minor complications were observed. In all the other cases detachment of the germinal membrane and subsequent reduction in size was observed, with a more or less complete solidification of the cyst and reduction of serology titers. Only one cyst recurred after 4 years and was treated again by PAIR. Long-term results indicate that in type I, II and III cysts, according to the Gharbi classification, PAIR is a first-choice method for treatment of liver hydatid cysts, especially in developing countries.