The understanding and management of coastal zone processes and resources is of great economic and social importance as at least half of the world's population resides and works within the coastal zone. Coastal zones have been greatly exploited by man for establishment and growth of industry, resource extraction, tourism and urbanization, which have led to the evolution of thriving coastal economies. The over-development of the coastal areas has also brought about a multitude of negative environmental impacts such as the effects of improper industrial and human waste management, accelerated erosion and deposition, eutrophication, destruction of marine life and overall decrease of bio-diversity. This paper proposes a method and tool for improved decision aid in integrated coastal zone management (ICZM). It discusses the advantage of implementing, in a spatial decision support system, the most efficient strategies for data capture, integration, analysis and modelling, for the assessment of impacts deriving from possible development scenarios. The importance of integrating socio-economic and biophysical parameters in the context of ICZM and the need to define environmental indicators on which decision-making processes are based, are outlined. (C) 1998 Elsevier Science Ltd. All rights reserved.