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We report direct measurements of S-branch Raman-coherence lifetimes of CO 2 resulting from CO 2–CO 2 and CO 2–N 2 collisions by employing time-resolved picosecond coherent anti-Stokes Raman scattering spectroscopy. The S-branch (ΔJ=+ 2) transitions of CO 2 with rotational quantum number J= 0–52 were simultaneously excited using a broadband (∼ 5 nm) laser pulse with a full-width-at-half-maximum duration of∼ 115 ps. The coherence lifetimes of CO 2 for a pressure range of 0.05–1 atm were measured directly by probing the rotational coherence with a nearly transform-limited, 90-ps-long laser pulse. These directly measured Raman-coherence lifetimes, when converted to collisional linewidth broadening coefficients, differ from the previously reported broadening coefficients extracted from frequency-domain rotational Raman and infrared-absorption spectra and from theoretical calculations by 7%–25%.