The alkaline dissolution behavior of radial-type polyester microfibers during high-temperature alkali treatment and cold-pad batch alkali treatment was successfully monitored using a cationic dye-staining method. The weight reduction behavior of the alkali-treated microfiber fabrics and their staining behavior with a cationic dye were compared. In addition, the termination of dissolution monitored by both methods was confirmed by scanning electron microscopy. (c) 2005 Wiley Periodicals, Inc.