This paper emphasizes the significance of social infrastructure in understanding urban inequality. In addition to its economic opportunities, social infrastructure is one of the distinguishing characteristics of metropolitan areas. In cities of the 21st century, social infrastructure is not equally accessible to all residences. For the development and sustainability of urban life, social infrastructure is fundamental. In terms of establishing a sense of belonging and integration to contemporary urban life, social infrastructure is highly crucial especially for refugees and rural migrants who migrate to the periphery of big cities. By evaluating the findings of this study conducted in Esenler District, we aim to contribute to research dealing with urban inequalities in Istanbul from the perspective of social infrastructure. To fill a gap in the literature, the social infrastructure of the Esenler District, which consists of rural-to-urban migration, refugee flow, and the working class in Istanbul's periphery, was analyzed by comparing it to other districts. The database created from various data sources and satellite images is presented with thematic maps. According to the findings, there is a significant divide between the central and peripheral districts of Istanbul in terms of social infrastructure. This inequality manifests itself in four ways: education, health, recreation, and fuel for housing. First, there are serious problems, such as the limited number of kindergartens, the high-class size in primary schools, and the poor quality of high schools in front of Esenler, which has a low education level. Second, there are only six healthcare centers in Esenler, where health services are inadequate compared to the central districts. Third, the green space cannot meet the recreational needs of the dense population in the district where unplanned and intensive construction has left no free space. Due to limited purchasing power, natural gas usage in Esenler is fairly low compared to central districts, despite the dense population. On the basis of these indicators, it has been concluded that the Esenler District, lacks the essential social infrastructure services necessary to maintain the city's health. Therefore, strengthening the social infrastructure on the urban periphery is a primary concern for developing a better understanding of urban inequalities, preventing problems, and making livable urban environments. [ABSTRACT FROM AUTHOR]