<p>The study examined the effects of the slum condition on the health of the dwellers in Osogbo, Nigeria. This is to assist in policy formulation in this area. The study hypothesised that there are no significant relationships between the socio-economic characteristics of residents and building quality as well as between building quality and health conditions in the selected slum areas. The buildings were selected for sampling using systematic sampling techniques for every tenth building. 5% of the household was considered which resulted administration of 313 questionnaires which were all retrieved. The findings revealed that all socio-economic attributes of the residents are generally poor and have significant relationship with the type of buildings in the area with <i>p</i> &lt; 0.01. Most of the houses in the area lacked basic facilities. The environment was poor, leading to the prevalence of deteriorating health challenges on the part of the residents. Evidence was the prevalence of environmentally related ailments in the area. Substantiated this was the results of the Cramer’s V coefficient calculated that shows strong relationship between the qualities of buildings and health of the residents. The study advises major renovation and upgrading, including the supply of urban basic services and poverty alleviation activities. Also, the study recommends widespread revitalisation and upgrading by providing basic facilities and poverty alleviation programmes. Maintaining public awareness of the value of a clean and healthy environment also requires a strong emphasis on environmental education and public enlightenment.</p>