Biodegradable Poly(glycolic acid) (PGA) nanofibers were prepared by irradiating a PGA fiber with radiation from a carbon dioxide (CO2) laser while drawing it at supersonic velocities and was collected as a nonwoven. A supersonic jet was generated by blowing air into a vacuum chamber through the fiber injection orifice. The flow velocity from the orifice was estimated by computer simulation; the fastest flow velocity was calculated to be 401 m s(-1) at a chamber pressure of 6 kPa. A nanofiber obtained using a laser power of 10 W and a chamber pressure of 6 kPa had an average diameter of 359 nm and a draw ratio of about 77,600. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 3078-3084, 2011