The title compound, C18H24NO3 (+)·Cl(-)·H2O, was synthesized by the reaction of propranolol hydro-chloride with acetyl chloride in chloro-form followed by slow evaporation in air. In the cation, the dihedral angle between the planes of the naphthalene ring system and the acetate group is 71.1 (2)°. An intra-molecular N-H⋯O hydrogen bond results in the formation of a non-planar pseudo-ring, with the ether O and the H atom displaced by -1.328 (2) and 0.65 Å, respectively, from the plane of the other ring atoms. The cation and anion are linked by an N-H⋯Cl hydrogen bond. The water molecule is linked to a methyl H atom by C-H⋯O hydrogen bond.