In this paper, we review existing food and nutrition security indicators, discuss some of their advantages and disadvantages, and finally classify them and describe their relationships and overlaps. In order to achieve this, the paper makes reference to the existing definitions of food and nutrition security (FNS), in particular as they have been agreed upon and implemented in the FoodSecure project (www.foodsecure.eu). The main existing conceptual frameworks of FNS predating the present paper are also used as guidelines and briefly discussed. Finally, we make recommendations in terms of the most appropriate FNS indicators to quantify the impacts of various shocks and interventions on food and nutrition security outcomes.