The title compound, C13H19N3OS, is a new thiazolidin-4-one derivative prepared and isolated as the pure (3aS,6R)-diastereisomer from (R)-thiosemicarbazone pulegone. It crystallized with two independent molecules (A and B) in the asymmetric unit. The compound is composed of a hexhydroindazole ring system (viz. a five-membered dihydropyrazole ring fused to a cyclohexyl ring) with a thiazole-4-one ring system attached to one of the pyrazole N atoms (at position 2). The overall geometry of the two molecules differs slightly, with the mean planes of the pyrazole and thiazole rings being inclined to one another by 10.4 (1)° in molecule A and 0.9 (1)° in molecule B. In the crystal, the A and B molecules are linked via C—H...O hydrogen bonds, forming slabs parallel to the ab plane. There are C—H...π interactions present within the layers, and between the layers, so forming a three-dimensional structure.