Quinoa (Cheopodium quinoa
), kañiwa (Cheopodium pallidicaule
), kiwicha (Amaranthus caudatus
) and tarwi (Lupinus mutabilis
) are ancient crops from the Andean region of South America. Recently, interest in these crops has grown, and worldwide demand for them has increased considerably. The aim of this study was to study the bioactive compounds and nutritional compositions of different varieties/ecotypes of quinoa, kañiwa, kiwicha and tarwi. Proximate, mineral, dietary fibre, fatty acid and amino acid compositions were evaluated. The content of phenolic compounds, tocopherols and phytosterols, and the folic acid and antioxidant capacity, were determined as well. The protein content of the grains was between 13.00% and 20.00%. More important than protein quantity is protein quality, which is demonstrated by the composition of the amino acids. All analysed grains, and especially the kañiwa, had very high lysine content. This amino acid is especially important in vegetarian diets because it is the limiting amino acid in cereal protein. The content of the total phenolic compounds in the studied grains was 27–58 mg gallic acid/100 g of sample. In quinoa, the principal flavonoids found were quercetin and kaempferol, in kañiwa quercetin and isorhamnetin. In kiwicha, no detectable amounts of flavonoids were found. Plant sterols (phytosterols) were another group of biologically active compounds detected. Andean lupin, tarwi, is very rich in oil, which has a beneficial nutritional composition. In conclusion, all studied grains have a very high nutritional value, are interesting sources of bioactive compounds and could be used as ingredients in health-promoting functional foods.