This study aims to determine total electric field strength (E) levels and its main sources in Samsun city center. To reach this goal extensive E and band selective E measurements were performed using Narda SRM 3006. The measurements were collected on the busiest streets of Samsun city during a journey of more than two hours on a vehicle moving with a certain velocity. On the basis of over 700 measurements E and E sources within the band were determined. It is seen from the results that the main sources of E were the base stations that operates at GSM900, GSM1800 and UMTS frequency bands. Because of difficulties encountered in band selective measurements (need for specific and expensive meters); a model that helps to obtain the three band selective Es in terms of E was proposed, and its performance was improved by using multilayer perceptron (MLP) artificial neural network system. With the use of this model; E levels of the three main sources can be determined from E in the environment up to 95% accuracy.