In the title 1:1 adduct, C(7)H(6)N(2)S·C(9)H(10)O(5), all non-H atoms of the benzothia-zol-2-amine mol-ecule are essentially coplanar, with a maximum deviation of 0.0286 (9) Å for the S atom. In the crystal, inter-molecular N-H⋯O and O-H⋯N hydrogen bonds connect two mol-ecules of each type into centrosymmetric four-component clusters.