A randomized controlled trial was carried out to study the efficacy of combined albendazole and praziquantel in the treatment of giardiasis in school-age children. Eighty-four children were randomly allocated to 3 groups: group 1 (n = 31) albendazole 400 mg combined with praziquantel 20 mg/kg; group 2 (n = 26) albendazole 800 mg as a single dose; group 3 (n = 27) tinidazole 50 mg/kg as a single dose. The treatment was considered curative when Giardia was not found in two consecutive stool samples. The parasitological cure rate was 74.2% for combined single-dose albendazole-praziquantel, 50% and 92.6% in the albendazole and tinidazole groups respectively (p = 0.0023). There was no statistically significant difference between the cure rates of the combined regimen and tinidazole (p > 0.05). This combined regimen was considered safe, with only minor side-effects being observed. Of the single-dose regimens, tinidazole still achieves the highest parasitological cure rate for giardiasis. The albendazole-praziquantel combined regimen may be an alternative single-dose therapy for giardiasis in children, especially as this combination will eradicate common intestinal protozoa and co-existing helminths. Whether the dosage of this combination treatment should be adjusted for G. intestinalis remains to be established by further study.