In the title compound, C(13)H(15)FN(2)S, the dihydro-pyrimidine ring is essentially planar, with a maximum deviation of 0.086 (3) Å from the mean plane of the rest of the ring for the dimethyl-ated C atom. The benzene ring is almost perpendicular to the dihydro-pyrimidine ring, with a dihedral angle of 83.97 (14)°. The crystal packing is characterized by centrosymmetric dimers resulting from pairs of inter-molecular N-H⋯S hydrogen bonds. There are also C-H⋯π inter-actions.