This paper analyzes factors affecting pure orange juice purchasing decisions of consumers in Bangkok Metropolitan area. The data used in this research were from interviewing 400 consumers in Bangkok Metropolitan area who used to buy pure orange juice. The data were collected during September to October 2008. The descriptive analysis techniques and Conjoint Analysis were applied. The results showed that certificate of standard and quality assurance was the most important factor which influences pure orange juice purchasing decisions of consumers followed by nutrition and price factors, respectively. Types of oranges and packaging were relatively insignificant factors affecting the consumer’s decisions.