Rate coefficients for the relaxation of vibrational excited oxygen molecules, including both vibration-to-vibration (V-V) and vibration-to-translation (V-T) energy exchange, have been calculated using a semiclassical method and a new potential energy surface for a large interval of initial vibrational quantum numbers (1 less than or equal to v less than or equal to 29) in the temperature range between 50 and 1000 K. (C) 2002 Published by Elsevier Science B.V.