In Kenya, as in other developing countries, diarrhea is among the leading causes of child mortality. Despite being easy to prevent and treat, care seeking for major child illnesses including diarrhea remains poor in the country. Mortality due to diarrhea is even worse in informal settlements that are characterized by poor sanitary conditions and largely unregulated health care system among other issues. The study aims to examine the health care seeking practices of caregivers of children under 5 with diarrhea in two informal settlements in Nairobi, Kenya. The article used data from a maternal and child health (MCH) prospective study conducted between 2006 and 2010. Results show that more than half (55%) of the caregivers sought inappropriate health care in the treatment of diarrhea of their child. Of the 55%, about 35% sought no care at all. Use of oral rehydration solution and zinc supplements, which are widely recommended for management of diarrhea, was very low. The critical predictors of health care seeking identified in the study are duration of illness, informal settlement of residence, and the child’s age. The study showed that appropriate health care seeking practices for childhood diarrhea remain a great challenge among the urban poor in Kenya.