The present invention relates to topical pharmaceutical microemulsions of cyclosporine A comprising a half (C 1 -C 4 ) alkyl esters of poly (methyl vinyl ether-co-maleic anhydride) (PVM/MA) copolymers. The invention also relates to a process for the preparation of said compositions and to their use in the prevention and/or treatment of several diseases, particularly psoriasis and atopic dermatitis.