Abstract: THIS INVENTION DISCLOSES APROCESS FOE THE PREPARATION OF ANOVEL STABLE - CRYSTAL FROM OF LMATINIB MESYLATE WHICH COMPRISES SLURRYING IMATINIB BASE IN ISOPROPANOL AT ROOM TEMPERATURE FOLLWED BY ADDITION OF METHANE SULFONIC ACID AND MAINTAINING THE TEMPERATURE BETWEEN 75-80 C FOLLOWED BY FILTRATION.