This work aim at evaluating GSM signal strength in terms of network service bars and to determine the frequency of the occurrence of the network service bars, also to provide useful suggestion that may improve the quality of signal strength in Mubi. The measurement was conducted at the center of the foot ball pitch of Adamawa state University Mubi. Total of 700 observations were made for the two Operators from 10/01/2010 - 24/01/2010, the investigation revealed that 3 – 4 bars seems to appeared more frequent. The evaluation established that the quality of the GSM signal strength is fair but not sufficient enough to meet up with customer’s satisfaction. Therefore the quality of signal strength needs to be improve to meet up with customers requirements in Mubi town.