The paper shows the urban development of Mostar mahalles and deals with the dilemma of their number from the 16th to the late 19th c. when the city came under the Austro-Hungarian administration. Based on the known defining elements of the mahalle, the number, construction date, location and size have been deter- mined for the Mostar mahalles, thus giving insight into Mostar's urban develop- ment in 16th-19th c. The research shows local particularities of mahalles and their status as autonomous residential urban units in the Ottoman period.