The objective of this study was to explore the model by identifying factors affecting consumer's purchase intention and to assess the actual purchasing of organic food products in Thailand. The finding demonstrates that knowledge positively affects attitudes toward organic food consumption. The factors affecting the purchase intention are attitude, perceived behavioral control, subjective norm and health consciousness. The study also investigates if the purchase intention, demographic characteristics (income and education) and perceived product attributes (premium price, trust, variety and availability) can be used to explain and predict consumers' actual purchase behavior. The recommendation of this research is that firms should concentrate on creating marketing strategies which influence the personal determinants by combining the demographic and product attributes factors. In particular, to develop and expand organic food markets in the future, firms should aim to modify the attitudes of consumer segments in the mass market. This can be done by implementing marketing campaigns that enhance organic knowledge associated with the health benefits, followed by the benefits in terms of the environmental and societal way.