Prayer hall, where traditional Muslim prayers take place, is the most important element of Masjids (mosques). Prayer halls are historically shaped as simple orthogonal walled spaces. Over time, little changes have occurred to them. Recently, with the evolution of architectural schools of thought and the advent of new construction and electromechanical systems, prayer halls have been subject to creativity and experimentation. Architects designed prayer halls with different shapes, spatial configurations and forms which, in some instances, contradict with the essentials of prayer. This research attempts to monitor and classify different types of contemporary prayer halls according to their spatial configuration with special reference to the Saudi Arabian context. Taking the city of Jeddah as a case study, a representative sample of masjids is surveyed, documented, analyzed and classified. The analysis is based on shape, enclosure, symmetry and complexity of prayer halls space. The study concludes basic and non-basic prayer halls and their corresponding bisects. The classification, however, constitutes a base upon which design criteria for prayer halls across the Islamic countries can be built.