Cottage industries comprise a sub-group of informal sector income generation activities which are conducted in the home environment and organized around families or households. Cottage industry workers may be at risk of exposure to harmful substances associated with their work, and given the lack of separation of cottage industry activities from living spaces, their families and neighbors may similarly be at risk of exposure. This study was undertaken to determine the extent and nature of cottage industries in five neighborhoods in Johannesburg (South Africa) A cross-sectional survey was conducted across five communities in Johannesburg in 2012. Data on metal-related cottage industry activities were collected through the administration of a pre-structured questionnaire. Metal-related cottage industry activities were defined as car repairs, spray painting, scrap metal recycling, electrical appliance repairs, welding, hairdressing and metal jewelry making. One fifth of the households interviewed were operating one or more cottage industries associated with the use of toxic substances. Therefore, the potential exists for associated ill health effects in a considerable proportion of the population. Further research is needed to fully assess exposure to the harmful aspects of cottage industry, as are scaled up campaigns to increase awareness of the risks and correct handling of toxic substances.