481 pregnant women attented at first consultation from a São Paulo city suburb-subdistrict of Butantan- São Paulo State, Brazil, from April to October of 1988, were investigated regarding the prevalence of verminosis. The mean age was 24,5 years (range 14-46), the average family income was 0.97 PCMW (per capita minimum wage) and the average number of members of the family was 4 (1 to 15). The verminosis prevalence was 45,1% among the women. The most frequent parasites were: Ascaris lumbricoides (19,0%), ancilostomideos (16,7%) and Trichuris trichiura (15,9%), The verminosis prevalence was significantly higher among the pregnant women (p < 0.05) who belonged to the families with income below 0.5 PCMW and greater than 4 members.