One thousand three hundred and fourteen cases of hepatic hydatidosis confirmed by surgical operation were analysed. Most of them contracted this disease in childhood, and hydatid cysts developed slowly without eliciting distinct symptoms until the occurrence of complications. The chief complaint was abdominal mass with pain in the right hypochondrium. The main complications in 1,314 patients were shown to be secondary bacterial infection of hydatid cysts (20.2%), cyst rupture (9.9%), portal hypertension (2.4%) and anaphylactic reaction (1.9%). By employing the advanced diagnostic technique especially the combined use of ultrasonography, roentgenography, CT scanning and seroimmunological diagnosis, the percentage of preoperative diagnosis might be raised to as high as 100%.