This paper aims to summarize the main consequences of illegal building development for the environment. The negative factors of this phenomenon will be discussed according to the available literature data. The illegally built buildings often disrupt the human living environment or ruin the landscape, agricultural or forest land. Buildings without urban permits might have negative impacts on biodiversity, and create geomorphological and hydrological problems (e.g. landslides, disturbance of watercourses or groundwater flows, etc.), which further could lead to many accidents, i.e. floods or inadequate water supply, food chain disruption, and pest appearance. Buildings with poor energy efficiency performance have negative impacts regarding climate change, contribute to atmospheric pollution and overconsumption of natural resources, especially of fossil fuels. The negative impacts range from aesthetic deterioration of landscape, threats to biodiversity and soil degradation to increased vulnerability of human settlements and health, local water contamination or drying of households’ draw wells. Uncontrolled generation of waste during building construction and use, as well as its disposal, especially in urban areas, could have major negative environmental impacts.

International scientific conference Environmental impact of illegal construction, poor planning and design IMPEDE 2019; Conference proceedings; October 10-11, 2019, Belgrade