The hydatid disease known as hydatidosis or echinococcosis is a cyclozoonotic disease widely distributed in the viscera and other organs of humans and animals. The aim of the present study was to evaluate the efficacy of different concentrations of selenium nanoparticles (Se NPs) (100, 250 and 500μg/ml), albendazole sulfoxide (ABZ sulfoxide) (50μg/ml) and
NaCl 0.9% as control with different exposure times (10, 20, 30, 60 min and 3 days) on protoscoleces of Echinococcus granulosus (E. granulosus). They were cultured in test tubes containing RPMI 1640 medium. Viability was examined by use of 0.1% eosin solution and scanning electron microscopy (SEM) was performed for different samples. Exposure to Se NPs at 100μg/ml had a scolicidal effect 100% after 60 min and 3 days only while they killed 93.7%, 95.3%,98.7% at 10, 20 & 30 min application respectively. Also, on exposure to a concentration of 250 μg/ml, the scolicidal activity of Se NPs was 100% after 20, 30, 60 min and 3 days while it was 99.7% after 10 min. On exposure to a concentration of 500μg/ml of Se NPs, all protoscoleces (100%) were killed at all times. Furthermore, exposure to albendazole sulfoxide exhibited partial scolicidal efficacy. SEM of different samples showed obvious alterations with Se NPs 500 μg after 3 days of exposure included invaginated scolex, degenerated rostellum and more severe affection of internal tissue with loss of integrity of the tegument and appearance of blebs.