The crystal structure of the title compound {systematic name: (S)-(+)-N-[1-(2-chlorophenyl)-2-oxocyclohexyl]methanaminium chloride}, C13H17ClNO+·Cl−, was determined at 90 (2) K. The (S)-(+)-ketamine hydrochloride salt is a well known anesthetic compound and is dramatically more potent than its R isomer. In the title compound, the cyclohexanone ring adopts a chair conformation with the oxo group in the equatorial orientation. The methylamino and 2-chlorophenyl groups at the 2-position have an equatorial and an axial orientation, respectively. The packing of ions is stabilized by an infinite one-dimensional ⋯Cl⋯H—N—H⋯Cl⋯ hydrogen-bonding network, involving NH2
+ groups as donors and chloride anions as acceptors