Due to the large increase in the population, the process of rapid urbanization and the strong development of technology, gray infrastructures have developed in cities. The basic and mostly only function of gray infrastructure is drainage or transportation. Gray infrastructures include: sewage system, waste water treatment devices, roads, sidewalks, parking lots, railway or tram tracks, the area around buildings of public and social purpose, etc. Urbanization of space has damaged natural relationships. Floods are a big problem in urban areas, which are becoming more frequent in the time of climate change. Gray infrastructure also has a great influence on the increase in floods and flood damage. Traditional gray infrastructure is necessary and inevitable for the functioning of urban environments, but it can often be improved with solutions originating from nature. In order to mitigate the consequences of gray infrastructure in urban areas, green and blue infrastructures are installed in addition to gray infrastructures. In contrast to gray infrastructures, green-blue infrastructures represent a strategically planned network of natural and semi-natural areas, ranging in size from rain gardens to green streets, that are designed and managed to provide a wide range of environmental, economic and social benefits, including improved water quality. Integrated gray green blue infrastructures are an example of design for sustainability. Using the example of the city of Osijek (eastern Croatia), the paper will show the possibilities of applying integrated gray green blue infrastructures.