This paper presents an evaluation of the security architecture employed in the General Packet Radio Services (GPRS). More specifically, the security measures applied to protect the mobile users, the radio access network, the fixed part of the network, and the related data of GPRS are presented and analyzed in details. This analysis reveals the security weaknesses of the applied measures that may lead to the realization of security attacks by adversaries. These attacks threaten network operations and data transfer through it compromising end-users and network security. To address some of the identified security weaknesses, a set of security enhancements that aims at improving the GPRS security architecture and providing advanced security services to user data traffic is proposed. The proposed enhancements can be easily integrated in the existing GPRS technology, minimizing the required changes.