Urbanisation and its effects is one of the biggest and most critical environmental issues facing the world. In the present study, we evaluate the impact of urbanisation on the picture-winged flies (family Ulidiidae) communities in Wadi El-Natroun Depression, by assessing the changes in abundance and diversity. Six sites, each measuring about 2.1 ha, were determined: three sites (A1, A2, A3) are in an open area out of the city, and three sites (B1, B2, B3) are on the periphery of the city surrounded by inhabited buildings and assumed to suffer from anthropogenic activities (urbanised sites). The fly sampling was conducted monthly from January to December 2015 using sweep nets. Total abundance and species diversity of ulidiids in open sites were significantly higher than in urbanised sites. A similar population trend was recorded for Physiphora alceae (Preyssler) and Physiphora smaragdina (Loew). These species appear in early spring and increase gradually but were almost eliminated by the beginning of the fall. A bimodal seasonal profile was observed with two peaks of Ulidia fascialis Hendel density: April and July. The correlation between species abundance and temperature was positive, but it was only significant with P. alceae in the urbanised area and with P. smaragdina in the open area. In contrast, an inverse correlation was recorded between species abundance and relative humidity; however, it was only significant with P. alceae in open and urbanised areas. A scatter plot generated from a principal component analysis (PCA) of species abundance showed a clear grouping of the study sites based on whether they were open or urbanised. The results of the present study showed that the picture-winged flies were directly affected by the habitat changes related to urbanisation. Both species abundance and diversity were dramatically reduced in the urbanised area. Consequently, these flies could be potential habitat quality indicators.