In this research 783 child of Day care centers (D. C. C) of Qazvin Alvand, Industrial Cities had stoll examination for Giardiasis.
Results were: Giardiasis was found in 13.5 % of children with peak incidence in 4-5, 6-7 years, more in female than male, incidence of Giardiasis were increased with decrease of Educational Level of mothers and increase of family members. Giardiasis was more in D.C.C of industrial, Alvand cities than Qazvin. D.C.C.