**Abstract**

Food allergies due to eating habits, pollution, and other factors are a growing problem in Western nations as well as developing countries. Symptoms of food allergies include changes in the respiratory and digestive systems. Legumes are a potential solution to the enormous demands for healthy, nutritive, and sustainable food. However, legumes also contain families of proteins that can cause food allergies. Some of these legumes include peanut, pea, chickpea, soy, and lupine. It has been shown that processing can alter the allergenicity of legumes since thermic and enzymatic resistance can affect these properties. Cross-reactivity (CR) is an allergy feature of some allergen proteins when the immune system recognizes part of the common share sequences (epitopes) in these allergic proteins. The research about molecular allergy includes comparisons of immunoglobulin E (IgE) and T-cell epitopes, assessment of three-dimensional structure and comparison of secondary structure elements, posttransduction modifications analysis by bioinformatic approach, and post-transduction modifications affecting epitopes properties may facilitate molecular tools to predict protein allergic behavior establishing prevention measurements that could promote the use of legumes and other seeds. This chapter provides an overview of the structural features of the main allergen proteins from legumes and their allergenic potential.

**Keywords:** food allergy, cross allergenicity, legumes, allergen proteins, soy, lupine
