In the title compound, C(17)H(15)N(3)O(5)S, the 2,3-dihy-droxy-benzaldehyde unit is oriented at a dihedral angles of 16.83 (10) and 78.87 (6)° with the anilinic and 5-methyl-1,2-oxazol-3-amine groups, respectively. An S(6) loop exists due to intramolecular O-H⋯N hydrogen bonding. In the crystal, inversion dimers with R(2) (2)(8) rings are formed due to N-H⋯N hydrogen bonding between the 5-methyl-1,2-oxazol-3-amine groups. These dimers are inter-linked by O-H⋯O hydrogen bonds, forming chains along [101] and resulting in R(2) (2)(26) rings. π-π inter-actions occur between the central benzene rings with a centroid-centroid distance of 3.7928 (16) Å.