The title compound, 2-amino-4,6-dimethylpyrimidine 2-hydroxybenzoate was studied by X-ray diffraction methods. This compound crystallized in a monoclinic system; space group P2(1)/n with the unit cell parameters a = 7.5380(14) A, b = 20.246(4) A, c = 9.2029(17) A, β = 108.594(3), V = 1331.2(4), Z = 4. The hydroxybenzoic acid group has been protonated by the aminopyrimidine moiety. The neighbouring two pyrimidine are bridged by N3–H3A···N2 hydrogen bonds, and the constituting dimers are linked together to form a discrete unit, these units, in turn, are linked together by C–H···O interactions. The protonated N1 atom is attached to the carboxyl group (O2) of the neighbouring phenyl by a hydrogen bond, together with the N3–H3B···O3 hydrogen bond to form a eight-membered ring with graph-set notation R 2 1 (8). The C5 and O1 through hydrogen bond forms a supramolecular chain along the b-axis, which is further strengthened by O1–H1···O3 hydrogen bond, bridging the hydroxide radical and carboxyl via hydrogen bonded rings, R 1 1 (6). A novel compound, 2-amino-4,6-dimethylpyrimidium 2-hydroxybenzoate was obtained and its structure was studied by single crystal X-ray diffraction. This compound crystallized in a monoclinic system; space group P2(1)/n with the unit cell parameters a = 7.5380(14) A, b = 20.246(4) A, c = 9.2029(17) A, β = 108.594(3), V = 1331.2(4), Z = 4.