Rate coefficients for the vibrational relaxation of O-2(a(1) Delta, upsilon) by CO2 have been determined from the decay of fluorescence of the a(1) Delta(g) -> X-3 Sigma(-)(g) (upsilon-upsilon') transitions with upsilon = upsilon' = 1, 2 and 3. O-2(a(1) Delta, upsilon) molecules were produced by pulsed laser photolysis of ozone at a wavelength of 266 nm. The rate coefficients were measured to be (1.9 +/- 0.2) x 10(-14) cm(3)/s, (2.4 +/- 0.2) x 10(-14) cm(3)/s and (2.7 +/- 0.3) x 10(-14) cm(3)/s for upsilon = 1, 2 and 3 respectively. (C) 2017 Elsevier B.V. All rights reserved.