A process for the preparation of methyl 1,1,N-trimethyl-N-(3,3-diphenyl-propyl)-2-aminoethyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-pyridine-3,5-dicarboxylate (lercanidipine) of formula I comprises reacting an acid halide of 2,6-dimethyl-5-methoxycarbonyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid with 2,N-dimethyl-N-(3,3-diphenylpropyl)-1-amino-2-propanol in an aprotic solvent. The product can be isolated by industrially applicable crystallization techniques and is obtained in high yield as its anhydrous hydrochloride, a form which possesses high stability and low hygroscopicity.