Aiming to identify the prevalence and the social risk factors of the intestinal parasitosis in first grade school children of Campinas, State of São Paulo, Brazil.Cross-sectional descriptive and analytical study based in personal and social data obtained by interview and feces analysis of 146 children to investigate Ancylostomatidae, Ascaris lumbricoides, Endolimax nana, Entamoeba coli, Entamoeba histolytica, Enterobius vermicularis, Giardia lamblia, Hymenolepis nana, Iodamoeba bütschlii, Schistosoma mansoni, Strongyloides stercoralis, Taenia sp and Trichuris trichiura.The prevalence of Ascaris lumbricoides was 12.3% and of Giardia lamblia was 8.2%. The prevalence of intestinal parasitosis, in general, was 30.8%. The social risk factors for intestinal parasitosis were low maternal (OR=2.3) and paternal education (OR=3.9), small house (OR=3.0), large household (OR=2.7) and proletarian group (p=0.02). After adjusting for social variables, intestinal parasitosis was predicted by paternal education (p=0.003).The role of health education is important for disease prevention and the school is a natural place to reach the community living next to it.