Squatter settlements are the most important urbanisation problem of developing countries. In Turkey after the 2nd World War, squatter problem gained great importance with rapid and continuous migration from rural areas to urban centres. Squatter areas began to appear in the vicinity of industrial developments in the big cities. Today the number of dwellings described as squatter in Turkey is 2.000.000, and a significant percentage of these dwellings is in the Istanbul Metropolitan Area. In spite of the various legal arrangements, the rapid increase of squatter dwellings could not be prevented. The first comprehensive legal precaution was the Squatter Act No. 775 dated 1966, which suggested improving the conditions of existing squatters, to demolish the poor quality squatters, and to construct the squatter prevention areas. In the 1970's, squatter owners began to construct additional storeys with speculative reasons. The squatter areas consist of multi-storey houses had been legalised by various laws by making the improvement and development plans in the 1980's. The aim of the paper is to examine the spatial distribution of squatter settlements in Istanbul having different physical, social and legal characteristics, and to discuss the results of legal approaches adopted in various periods of time.