A cross-sectional investigation was made into ascariasis and nutritional status in Panamanian preschool children from October 1983 to July 1984. Within this framework, an analysis was undertaken of possible relationships between a range of intestinal helminthiases and the socioeconomic status of the participants. Attention was paid to caregiver's education, parental occupation, family earnings, quality of housing and sanitation in the assessment of socioeconomic status. On this basis, strong associations were established between the socioeconomic status of the children and infection with Ascaris lumbricoides, Trichuris trichiura and hookworm. In general, the prevalence of single and multiple helminth infections was significantly higher in children living in housing made of wood or bamboo than in those living in housing made of concrete blocks. The same pattern applied to levels of sanitation. Ascaris lumbricoides occurred more frequently in children of mothers with the least formal education and in children living in relatively crowded conditions. Evidence was also obtained to indicate that the intensity of the intestinal helminth infections was greater in the children from the poorer environment. Since children from poorer socioeconomic conditions might be more exposed to infective stages than those from a better environment, the possible role of socioeconomic factors in contributing to the predisposition of some individuals to harbour large worm burdens of intestinal helminths was briefly discussed.