This paper will throw light on the nature of Ottoman neighborhood, mahalle, in the sixteenth century through the analysis of court records. The Ottoman mahalles have often formed a statistical basis for the social historians dealing with the pre-modern Ottoman urban history. While mahalle is usually interpreted as a communal and administrative ensemble with a mosque as its nucleus, the nature of mahalle itself has not been fully analyzed heretofore. This is because official documents, which researchers usually rely on, seldom reveal how one was defined and formed. The first volume of court records of Uskudar, a suburban district of Istanbul, contains approximately one thousand records of inheritance, purchase and sale, punishment, and so forth, from the first quarter of the sixteenth century. It also provides precious examples for the study of mahalle itself. First of all, mahalle system does not seem to have been widespread and established in Uskudar during the period. Unlike other contemporary Ottoman cities such as Bursa or Karaman, the early court records of Uskudar rarely registered mahalles where relevant persons resided. Considering Uskudar’s later volumes of the late sixteenth century registered mahalles methodically, the lack of mahalle names indicates the absence of such a social structure during the first quarter of the sixteenth century. Secondly, attempts to create mahalles in Uskudar can be pointed out in the records. One of few examples that registered a name of mahalle concerns with an appointment of government official. When one was involved in formal affairs, his/her residence mahalle should have been recorded as a social identity, although in reality there was no definite mahalle organization there as mentioned. Uskudar was a newly-populated district after the conquest of Istanbul in 1453 where the development was at the hands of immigrants, not the central government. When the latter tried to put the district under its control for various reasons, such as taxation or security during the sixteenth century, loosely formed Uskudar was reorganized into mahalle-based society. Thus, a mahalle at the beginning can be regarded as an official and administrative organization, rather than local and spontaneous.