This paper discusses the implications of current practices in the design of contemporary mosques in Saudi Arabia on their acoustical performance. Different functions of the mosque are described along with the unique modes of worships reflected in the changing relative speaker to listener positions during prayers. Different postures of a speaker and listeners in the mosque and how they influence the listening conditions are also discussed. The physical characteristics of the mosque, which have been generally retained from the past despite the giant developments and social changes in the country, are introduced and their respective acoustical impacts are evaluated. Acoustical parameters describing the special aural requirements and prevailing listening conditions in the mosque are highlighted. Such parameters include speech intelligibility, loudness, and the uniformity of the sound distribution. In addition, the use of sound reinforcement systems in the mosque is evaluated. Conclusions are drawn on the unique nature of the problem. It follows that the architectural design of the mosque in Saudi Arabia should be governed by the acoustical performance which should be responsive to the special hearing requirements in the space.