Following the Six Day War, June 1967, the incidence of Ascaris infection of the gastrointestinal tract has risen sharply in Israel as a result of the consumption of contaminated agricultural produce from undeveloped areas. We report three cases of Ascaris invasion into the biliary system, which caused signs of obstruction and ascending infection. These patients' biliary systems had been previously injured by calculus disease and repeated operations might have predisposed them to invasion by the parasite.