Abstract Quinoa, classified as a pseudocereal, presents greater nutritional value compared to traditional cereals. Considering the potential for cultivation presented by the species and the benefits of studying plant morphology and morphobiometry, this paper describes seed and seedling morphobiometric characteristics of quinoa (Chenopodium quinoa Willd.) cultivar BRS Piabiru during germination and emergence. To evaluate seed morphobiometry the 1000-seeds weight, moisture content, seed morphological characterization and the tetrazolium test were performed. The morphological characterization of germination and seedling emergence were performed by periodic observations during the development, allowing the description using pictures and drawings. Quinoa seeds cv. BRS Piabiru present an average diameter of 2.05 mm and 1.07 width. 1000-seeds weight of 2.68 g and moisture content of 11%. Externally, quinoa seeds present the pericarp as testa, the hilum and the raphe and, internally, the embryonic axis (cotyledons, radicle and hypocotyl-radicle), perisperm and endosperm. The germination is characterized as epigeal, phanerocotylar type, with radicle protrusion at 3 hours after sowing and complete formed seedlings at 24 hours after sowing. Emergence occurs at 9 days after sowing and plants are completely formed at 12 days after sowing.