Abstract: Intestinal parasite infections are major public health problems of children. The study aimed to assess the prevalence of intestinal parasites and associated risk factors among preschool children in Riyadh city. Samples were obtained from 255 preschool children (157 girls and 98 boys), a single stool sample was collected and examined microscopically for the presence of intestinal parasites using a formalin-ether sedimentation technique. The overall prevalence of parasites was 45 (17.7%), the most of them had diarrhea 40 (15.7%) was a significant difference, (p<0.05). The prevalence rate of infection in boys and girls were (20.4%, 15.9%), respectively. In all preschool children, the highest infection rate was (23.3%) among the age group ranged between 3-5 years. The study detected about seven types of intestinal parasites among preschool children, the most common parasites were Giardia lamblia (37.8%). In this study the relationships were observed between intestinal parasitic infection and some of socio-demographic factors. Concerning the parents educational level was highly significant difference (p<0.001). Working mothers, presence of house maid, attending day care centers and poor hygienic measures and moderate socioeconomic standards were played role as predisposing factors for transmission of infection. The prevalence of infection with intestinal parasites between two different area in Riyadh was no significant. The study indicated that parasitic infections are important public health problems. Thus, infection control measures and the development of awareness strategies to improve sanitation and health education should be considered.