In this paper, we rely on data from the 1995 Guatemalan Survey of Family Health (EGSF) to analyze the relationship between child illness and health seeking behavior. The EGSF is better suited to this type of analysis than most earlier studies because it contains detailed calendar information -- from a large random sample of mothers in rural Guatemala -- on the nature and timing of illness and treatment behavior for children age five and below. Information on illness was collected for a total of 3,193 children. This analysis is based on 870 of these children who began a diarrheal or respiratory illness during a 13-day period prior to interview. Estimates are derived from binomial and multinomial logistic models of the probability of seeing any or a specific type of provider on a given day of illness as a function of characteristics of the illness and the child. The results indicate that modern medical care plays a major role in the treatment of infectious illness among children in rural Guatemala, with visits to pharmacists, doctors and the staff at government health facilities occurring much more frequently than visits to curers and other traditional practitioners. In general, families are much more likely to seek a provider when a child experiences fever and gastrointestinal symptoms, as compared with respiratory and other symptoms, and when a mother perceives the illness to be serious. The estimates also indicate that infants, low parity children, and children assessed as having generally been in good health are more likely to visit providers than other children. However, the particular associations often vary by type of provider.