The title compound, C(9)H(8)N(3)O(+)·Cl(-), was isolated from a liquid culture of streptomyces sp. In the cation, the ring system makes a dihedral angle of 0.2 (2)° with the amide group. The protonation creating the cation occurs at ome of the N atoms in the quinoxaline ring system. In the crystal, the ions are linked through N-H⋯O and N-H⋯Cl hydrogen bonds, forming a two-dimensional network parallel to (10[Formula: see text]).