In the crystal of the title mol-ecular salt, C(5)H(8)N(3) (+)·C(8)H(5)O(4) (-), the diamino-pyridine cation and the phthalate anion are linked by a pair of N-H⋯O hydrogen bonds. Within the phthalate anion, an almost symmetrical O-H⋯O hydrogen bond is observed. The ion pairs are linked by further N-H⋯O hydrogen bonds, generating a two-dimensional network lying parallel to (10).