Hydatid cysts of the liver are known to occasionally rupture into the bile ducts and cause cholangitis. The histological features of this complication have not been adequately described in the literature. Herein is reported a case of severe eosinophilic cholangitis of the left hepatic lobe, occurring in a 24-year-old man with a large (16 cm) hydatid cyst, which obstructed and eroded the left hepatic duct. The patient presented with upper abdominal discomfort and low-grade fever of 3 weeks' duration. Sections of the left lobectomy specimen showed marked inflammatory infiltrates in the portal tracts, predominantly composed of eosinophils, extensively involving bile ducts of all sizes. Occasional small bile ducts were replaced by epithelioid cell granulomas surrounding eosinophilic microabscesses. The inflammatory infiltrates extended into the lobules, resulting in marked hepatocyte loss. This case demonstrates that echinococcosis may cause severe eosinophilic cholangitis with extensive parenchymal destruction, apparently resulting from a hypersensitivity reaction to parasitic antigens.