Energy savings from the utilization of daylight will be influenced by the amount of external daylight incident on the external surface of the window plane. Therefore, savings from daylight will vary from a place to another, based on the prevailing sky conditions in the climate concerned. This paper aims to investigate the potentiality of natural light if used a source of internal illuminance in buildings in the Eastern coast of Saudi Arabia. This includes providing information about daylight performance in the area. (C) 2001 Elsevier Science Ltd. All rights reserved.