Background & Objectives: Intestinal infestation is among the most common infections in the world, being responsible for considerable morbidity and mortality. The objective of this study was to determine the prevalence of intestinal infestation and related risk factors among students of primary schools in Ardabil.

  Methods: This cross-sectional and descriptive study was conducted in 24 primary schools of Ardabil in 2003. A total of 1070 school children between 7-13 years of age (527(49.3%) boys and 543(50.7%) girls) took part in this study. Fecal specimens were collected by random sampling and were examined for ova, larva and cysts of intestinal parasites using direct wet mount and formalin-ether concentration methods.

  Results: A total of 1 0 species were identified, Giardia lamblia (14.2%), Blastocystis hominis (10.2%) and Entamoeba coli (4.1%) were the most common parasites, respectively, the over all prevalence rate for at least one parasite was 27.7%. There was no statistically significant difference in prevalence of parasites by sex, age, class grade and rate of infection (p>0.06).