Abstract: Olopatadine can be obtained by means of a process comprising hydrolysis of a compound of general formula (II), wherein Y is OR1, wherein R1 is C1-C7 alkyl, C3-C7 cycloalkyl, aryl, arylalkyl, or heterocycle; or NR2R3, wherein R2 and R3, independently from each other, are C1-C7 alkyl, aryl, arylalkyl, or R2 and R3 together with the nitrogen atom to which they are bound form a heterocycle of 3 to 7 members, obtained by means of a process comprising reacting the corresponding ester or amide of 6,11-dihydro-11-oxodibenz[b,e]oxepin-2-acetic acid with a suitable Wittig reagent, in the presence of a base in a reaction medium comprising an organic solvent.