In the title compound, C(8)H(9)N(5)O, the mean planes through the pyrimidine and triazine rings form a dihedral angle of 2.83 (16)°. The amino group adopts a trigonal-planar configuration and forms an intra-molecular resonance-assisted N-H⋯O=C hydrogen bond with the carbonyl group. In the crystal, mol-ecules are linked via inter-molecular N-H⋯N hydrogen bonds into chains of C(2) (2)(6)[R(2) (2)(6)] motif. The molecules form two types of sheet parallel to (201) and (01), respectively.