Very little is known about the effects on adult health of environmental conditions in developing countries. Most studies have focused on child health and few have included environmental factors. The shortcomings are associated with difficulties in measuring health status for adults and the limited availability of data on environmental conditions in developing countries. Schultz and Tansel conclude their study stating "the next step in this field of research is to distinguish what variations in public policies or natural variations in environmental conditions combine to explain existing variation in adult morbidity among wage earners." According to UNICEF, over half the population of Brazil live in an unsanitary environment. Worldwide, nearly three billion people do not have access to even a minimally sanitary toilet. This study assesses the effects of demographic factors and key environmental conditions on adult health in Brazil. The research focuses on morbidity among wage earners and the impact of specific environmental conditions. The analysis is based on a household model developed by Schultz and Tansel and treats work absence due to health problems as a measure of adult health status. The data used are from the 1989 Brazilian National Health and Nutrition Survey and 1989 National Basic Sanitation Condition Survey. The first is a household survey that measured individual health and nutrition. The second survey provides data on basic environmental and sanitary conditions at the municipality level.