A study of intestinal parasites in school children in urban and rural areas of Tetouan (Morocco) was conducted. Before it was performed a comparative quantitative study of Faust's and Ritchie's techniques in order to optimize intestinal parasites diagnosis and to determine the techniques effectiveness. The Ritchie's technique resulted the most effective for the detection of both protozoan and helminthes, especially under conditions of low parasite burdens. The prevalence of intestinal parasites was 65% and 71% in rural and urban areas respectively. Overall, the prevalence of protozoa that was found was higher than the one detected for helminths. The most frequent of the intestinal parasites was the protozoa Blastocystis hominis and the most frequent pathogenic protozoa were Giardia lamblia followed by Cyclospora cayetanensis. Among the helminths Trichuris trichiura, Hymenolepis nana, H. diminuta, Enterobius vermicularis, Taenia saginata, Ascaris lumbricoides and Fasciola hepatica. Giardia lamblia showed notable differences between boys and girls in urban areas. To compare the prevalence of parasites in children with the same sex in different areas the differences were only found in boys infected by B. hominis, G. lamblia and E. nana. Multiple parasitism appeared in 29% of the samples presenting two, three or four parasites.