In Persian Medicine (PM), food is considered as a basic concept, the proper understanding of which, will prove beneficial in nutrition of healthy individuals and diet therapy of patients. The objective of this article is to examine the defining attributes of the concept of food in PM. Concept analysis was performed using Walker & Avant's approach, comprising eight stages of 1) selecting a concept; 2) determining the objective of analysis; 3) identifying all uses of the concept; 4) determining the defining attributes of the concept; 5) constructing a model case; 6) constructing borderline, contrary and invented cases; 7) identifying antecedents and consequences; and 8) defining empirical referent. The results showed that, the defining attributes of the concept of food in PM are: 1) replacement of body tissues and organs; 2) resemblance to tissues and organs; 3) adding to body quantity; 4) prerequisites for childbirth; 5) delicious and sweet or tasteless or greasy flavors; and 6) production of blood humors, warmth and moisture. In order to clarify the concept, borderline, contrary and invented cases were also presented. The results of this study can provide an objective and understandable picture of the use of the concept of food for researchers and open new horizons in nutrition and diet therapy.