This paper uses the 1995 Guatemalan Survey of Family Health (EGSF) to analyze the relationship between child illness and health seeking behavior. The EGSF contains detailed calendar data on the nature and timing of illness and treatment behavior for children age five and below; extensive information about the characteristics of mothers, families and communities; and data on the accessibility of traditional and biomedical providers within and near the community. The analysis is based on 870 children who began a diarrheal or respiratory illness during a 2-week period prior to interview. Estimates are derived from a multinomial logit model of the probability of seeing a specific type of provider on a given day of illness, as a function of characteristics of the illness, child, mother, and community. The results indicate that modern medical care plays a major role in the treatment of infectious illness among children in rural Guatemala. The symptoms associated with the illness, their perceived severity, and mother's beliefs about their causes are important determinants of whether a child is brought to a provider and the type of provider visited. Poverty is a serious constraint on a family's choices about how to treat children's illnesses, whereas education and ethnicity have little effect on treatment behavior when income is held constant. In addition, the availability of modern health facilities within the community-both government-sponsored facilities and private doctors-has a substantial impact on the type of providers sought to treat children's illnesses.