In the title salt, C(6)H(10)N(3)O(2) (+)·C(7)H(7)O(3)S(-), the 2-amino-4,6-dimeth-oxy-pyrimidinium cation inter-acts with the sulfonate group of the p-toluene-sulfonate anion via a pair of N-H⋯O hydrogen bonds, forming a cyclic hydrogen-bonded R(2) (2)(8) motif, which in the crystal is linked by further intemolecular N-H⋯O hydrogen bonds, forming supra-molecular chains along the c axis. Furthermore, neighboring chains are inter-linked via weak C-H⋯O hydrogen bonds and C-H⋯π inter-actions, forming layers.