The use of quality seeds is fundamental to the success of any crop. In Brazil, it has been growing significantly the implementation of pastures areas, mainly of brachiaria. However, there are many difficulties to determination of quality of seeds from this genus of forages. With this, the aim with this work was to relate the characteristics of different substrates and the physiological potential of seeds of brachiariaMulato II. Was evaluated the germination of bared and treated seeds of brachiaria in the following substrates: germitest paper (described at RegrasparaAnálise de Sementes), sand and perlite in two gradations (small and large). According the results, was possible to conclude that the utilization of substrate small perlite, when used bared seeds, is more promising to evaluate the germination of brachiaria seeds cultivar Mulato II. For seeds treated, all substrates used are efficient to evaluate the germination of brachiaria seeds cultivar Mulato II. The substrate 100% small perlite achieved the desired index of germination of brachiaria described by the normative instruction 45 from 17 September 2013 (MAPA).