Disclosed is a method for the preparation of crystalline duloxetine hydrochloride, which has the systematic name, (+)-(S)-N-methyl-3-(naphthalen-1-yloxy)-3-(thiophen-2-yl)propan-1-amine, the method for preparation comprising (a) dissolving duloxetine in a first organic solvent to form a first solution (b) combining the first solution with a second organic solvent solution comprising HCl to form a second solution (c) adding the second solution to a third organic solvent to form a third solution (d) allowing duloxetine hydrochloride to crystallize out from the solution during a period of cooling at 0 - 10 degrees and (e) collecting the crystallized duloxetine hydrochloride, wherein the first organic solvent is dichloromethane, the second organic solvent is ethanol and the third organic solvent is hexane. Also disclosed is crystalline duloxetine hydrochloride which exhibits an X-ray diffraction pattern comprising peaks expressed in degrees two-theta at approximately 11.95, 13.93, 14.5, 14.76, 16.19, 17.97, 18.62, 18.82, 20.79, 21.26, 21.44, 21.76, 22.12, 22.28, 23.08, 23.28, 24.06, 26.31, 26.94 and 29.86, plus or minus 0.2 for each value.
