Gastronomy tourism, besides being the most important means of economic development, it is also the most significant part of the fastly developing cultural tourism market. Many recent researches emphasized that the culinary culture of a target destination has a significant part in the travel experience. The initial aim of this work is to research the effect of gastronomy on the marketing of destinations. The research has been made in Istanbul on 93 type a travelling agencies. This research focuses on a quantative feedback of the role of gastronomy in forming a positive feedback on the forming of an expression and a label value in the marketing of Turkey and Istanbul. The findings have been researched in relevance to the related literature. The result of the so-called research proves that by means of marketing Istanbul, gastronomy has a strong image and brand value. Results also indicate that it might be possible to market Istanbul through Ottoman Palace cuisine and Turkish tourism and that people who take part in culinary tourism are mainly tourists between 35-55 or upper ages who have a high level of income. Results also show that gastronomy tourism could be integrated into other tourism types, which would boost local development.