This study demonstrated emission of microplastic fibers derived from synthetic fibers (hereaftereferred to as “fibers”) during household washing, and evaluated reduction in fibers with lint filtersd equipment in domestic washing machines made in Japan. We conducted replicatetwo types of front loader washing machine and weighed the mass of microplastic fibers collected e fibers than the front loader washing machine duringoximately 70% of the microplastic fibers of length over 3 mm were collected by the lint ter than 3 mm were discharged to the ough the lint filter. The filters installed in the front loader washing machines could hardly collect ge gaps.