The objective of this research is to develop a methodology for assessing environmental risks arising from the construction and demolition waste (CDW), considering some environmental criteria to identify the most critical locations. A field survey was conducted in seven municipalities in Brazil, which involved obtaining the CDW illegal dumping sites, through direct observation and photographic registration in the municipalities studied, for assessing environmental risks arising from the CDW illegal dumping and to identify areas with the highest risk of impacts according to environmental criteria. Each site was classified according to aspects such as distance between the irregular disposal points and water resources, plant cover, subnormal clusters, mean family income, parks and plazas, and health and education equipment. A total of 1252 irregular dumping sites were registered in the study area, distributed among the seven municipalities analyzed. In all municipalities surveyed, high-risk dumping sites were identified, although they do not represent most of the sites. Based on the application of this methodology in other municipalities, it will be possible to calibrate the score according to the social and environmental characteristics of each region, and it can be consolidated as a standard tool for assessing environmental impacts from the illegal CDW dumping.