This paper aims to provide an introduction to scenario-based thinking and planning and to encourage the use of this method in Small and Medium Enterprises (SMEs) by entrepreneurs. Because of their nature and size, the activities of SMEs in dynamic and indefinite environments are more than large companies. To maintain competitiveness, they have to anticipate market environmental changes and to be able to match their business activities to those changes. Scenario-based planning is a tool that can provide such capability. It increases companies? power in facing with environmental changes and decision makers will consider more aspects in selecting alternatives. The present paper reviews scenario-based analysis and its application in market forecasting. In parallel with this goal, some explanations in relation to scenario-based planning, historical background, applications and method of its use are presented first. Then, its application in SMEs is reviewed and finally, research model will be presented. Key Words: Decision Making, Market Forecasting, Scenario-based Planning, Small and Medium Enterprises (SMEs.)