This article reports the current status of organic market data collection in Europe and the United States, and discusses possible measures to improve the availability, reliability, and comparability of these data in Japan. Consumer panel data collection is the most likely method to tackle this task in Japan, though to utilize the data, all organic food products must be identified among all the food products sold in the domestic market. Also, for a market size estimate, an additional survey with producers is necessary to include sales of non-barcoded products, such as vegetables, fruits and rice. Stakeholders are advised to form a network for organic market data collection, and to decide whether to include non-certified organic products and sales in the organic catering sector in the market estimate.