To assess the therapeutic effects of long-term albendazole therapy in intraabdominal cystic echinococcosis Methods Fifteen patients with a total of 45 cysts were treated with albendazole with dosage regimen of 20 *!mg·kg -1 ·d -1 for an average of 2 5 years Repeated CT and ultrasound scannings (US) were performed after the end of therapy The duration of follow-up was 3 6 years on average The number, size and morpiology of cysts were compared before and after treatment Results The hydatid cysts were classified according to location and CT patterns into hepatic simple cysts, hepatic cysts with daughter cysts, hepatic/abdominal cysts and splenic cysts The hepatic simple cysts responded most favorably to albendazole therapy, with an overall cure rate of 88 7% The disappearance of cysts was observed in 43 0% of cases (15/35) Sixteen cysts (45 7%) became solidified or calcified, among which 8 cysts were completely calcified, 6 showed egg shell-like calcification of the cystic walls, and 2 showed solidification and calcification of cyst contents Four patients had large hepatic cysts containing daughter cysts; the daughter cysts all disappeared after treatment, but one patient relapsed with the reappearance of daughter cysts at 4-year follow-up Two splenic cysts also calcified Two patients had peritoneal cysts; one calcified and the other one reduced in size Among 15 patients treated, 9 were cured and 6 were improved There was no serious toxic reactions with continuous long-term therapy in a small series of patients Conclusions Continuous long-term albendazole treatment of intraabdominal cystic echinococcosis is safe and effective in the treatment of hepatic simple cysts, and some daughter cysts, peritoneal secondary cysts and splenic cysts No serious toxic reactions were found