The interest in the research about underexploited foods has increased in the last two decades. Pseudocereals have been consumed by the ancient populations for hundreds of years. These plants that do not belong to the family of cereals, but that have properties and uses similar to them, stand out among underexploited foods. Some of the most representative species are quinoa, amaranth, chia and buckwheat. They do not contain gluten but high valued proteins and peptides can be obtained from them, as well as other nutritional and bioactive compounds such as flavonoids, phenolic acids, fatty acids, vitamins and minerals. Anticancer, antioxidant, anti-inflammatory, hypocholesterolemic and antihypertensive properties have been found and postulated for pseudocereals protein derived peptides. These interesting characteristics of pseudocereals are producing an increase of the relevance of these crops. The purpose of this work was to carry out an exhaustive revision of the scientific literature describing the biological activities of peptides and protein hydrolysates obtained from the most widely studied pseudocereals: quinoa, amaranth, chia and buckwheat.