We present the first comprehensive catalogue of true flies from the northernmost territories of Pakistan, including Azad Jammu & Kashmir and Gilgit-Baltistan. In the current inventory, 64 genera and 153 species in 16 families are being documented. The total number of known species has been updated based on the availability of taxonomic literatures from Pakistan. In 2007, Insect Fauna of Azad Jammu & Kashmir was updated and it lists only 16 known species in order Diptera where as there is no such documented information so far available on the dipterous fauna of Gilgit-Baltistan. However, during the last few decades, relatively a few studies have been conducted on some major group of flies, i.e., Syrphidae, Sepsidae, Calliphoridae, and Tephritidae from Azad Kashmir and Gilgit-Baltistan. Among these, Syrphidae represents 53 species which is the highest number of species recorded, followed by Sepsidae and Calliphoridae with 20 and 18 species, respectively. The present diversity does not reflect the true species account in the northern areas; the important biogeographic area that exhibits a very heterogeneous fauna, not only because of the high mountains with valleys (the Hindu Kush and Karakoram ranges of the Western Himalayas) but also the junction points of the world’s two largest zoogeographical regions (the Oriental and Palaearctic). Some common families, i.e., Stratiomyidae, Asilidae, Bombyliidae, Muscidae, Conopidae, Pipinculidae, Tachinidae, and some other families which are common in high mountainous regions of northern Pakistan still need to be explored in the future studies. The complete locality data for each valid species are presented as the baseline for future studies from northern areas of Pakistan, i.e., Azad Jammu & Kashmir and Gilgit-Baltistan.