In the title compound, C(13)H(13)NO(4), the fused-ring system is nearly planar, with an r.m.s. deviation of 0.0408 Å. In the crystal, mol-ecules are linked into centrosymmetric dimers by a pair of N-H⋯O hydrogen bonds. The ethyl group is disordered over two positions in a ratio of 0.758 (6):0.242 (6).