The aim of this paper is assessment the performance of two Positioning methods, Uplink Time Difference Of Arrival (U-TDOA) and Assisted Global Positioning System (A-GPS) in Mosul city, Iraq. The study area is a (3×3 km) which covers the University of Mosul campus. Simulation is used to study the performance of U-TDOA method in urban area and measurements of A-GPS method are taken and the results of the two methods are compared. The effect of multipath, signal to noise ratio, shadowing, the configuration of base stations and the number of satellites in view on the positioning accuracy are investigated. The study is conducted on a real coordinates with the distribution of UMTS Base Stations (BSs) sites as the same existing Asiacell operator.