The present patent application relates to a process for the preparation of Duloxetine and its salts comprising reacting (S) - (+)-N, N-Dimethyl-3-(2- thienyl)-3-hydroxypropanamine or a salt there of with 1-fluoronapthalene in the presence of sodium hydride and potassium 4-methyl benzoate; N- demethylation via formation of phenylcarbamate to obtain Duloxetine which may then converted in to a pharmaceutically acceptable salt.