A new method called PAIR (Puncture-Aspiration of cyst contents--Injection of hypertonic saline solution--Reaspiration) was used as a percutaneous treatment of hydatid cysts. In 37 patients, 120 cysts were punctured. All patients had not been considered surgical candidates. The cysts were localized in the liver, peritoneum, spleen, kidneys, muscles, and bones. In 70% of patients, good results were obtained. Recurrence occurred in 5 of 120 cysts, all at the beginning of our experience when a low concentration of sodium chloride solution was injected. Moderate allergic reactions occurred during seven cyst aspirations. No anaphylactic shock, sudden deaths or dissemination of cyst contents were observed.