In the title compound, C10H11FN3O3S, the 2-fluoro-benzoyl and proponic acid groups maintain a trans-cis conformation with respect to the thiono C=S bond across their C-N bonds. The propionic acid group adopts an anti conformation about the C-C bond, with an N-C-C-C torsion angle of 173.8 (2)°. The amino groups are involved in the formation of intra-molecular N-H⋯O and N-H⋯F hydrogen bonds. In the crystal, pairs of O-H⋯O hydrogen bonds link mol-ecules into inversion dimers.