Poly(ethylene terephthalate) (PET) nonwoven fabric was prepared from microfibers obtained by using a carbon dioxide laser-thinning method. The PET nonwoven fabric obtained was made of the endless mircofibers with a uniform diameter without droplets. The fiber diameter can be varied by controlling airflow rate into the air jet and supplying speed of an original fiber into a laser-irradiating point. The fiber diameter decreased, and its birefringence increased as the airflow rate increased and the supplying speed decreased. When the microfiber prepared by irradiating the laser operated at a power density of 4.8 W cm(-2) to the original fiber supplied at S-s = 0.15 m min(-1) was dragged at an airflow rate of 30 L min(-1), the thinnest microfiber with a diameter of 3.6 mu m was obtained. (c) 2007 Elsevier Ltd. All rights reserved.