This study constructs a multi-dimensional index to measure consumer knowledge of functional foods. A nationwide survey in Finland shows that objective and specific knowledge are the most important components in the consumer knowledge index and that they distinguish experts from novices. Gender, education, income, and age serve as functional foods, which in turn affects attitudes towards health and, consequently, buying behaviour. The study extends the application of consumer knowledge literature to non-durables and edible products and provides further insights into the growing functional foods market as seen from the consumer perspective.