The household, workplace, outdoor and transportation environments pose risks to health in a number of different ways, from the poor quality of the air many people breathe to the hazards we face as a result of climate change. This problem is exacerbated by the high population growth rate of Metropolitan Lagos. This puts a lot of pressure on existing infrastructural and social services which further degrade the environment. Unfortunately, the poor are the most vulnerable to these health and environmental hazards. This paper focused on the social and environmental health risk factors associated with vulnerable groups in Metropolitan Lagos. Specifically, this paper reports how these factors affect the health conditions of these groups of people. Metropolitan Lagos is stratified into various neighbourhoods according to income level and density. Three low income/high density areas were selected for study. The direct observation, administration of questionnaire and Focus Group Discussion (FGD) methods of data collection were employed in addition to the use of secondary based facility data. Information were sought on environmental risk variables like the quality of water, sanitary conditions, refuse disposal types, drainage conditions, sources and intensity of air pollution and sources of energy for cooking. These variables were correlated against health indexes like morbidity and mortality. Results show a strong association between environmental factors and the health status of people especially the poor in the study area.