We present measurements of collisional broadening coefficients, obtained at atmospheric pressure, by polarization spectroscopy. Using tunable single mode laser radiation at ∼2 μm, high-resolution infrared polarization spectra were recorded for CO₂–Ar and CO₂–He binary mixtures. The recorded polarization spectra were fitted with a Lorentzian cubed function form to obtain the broadening coefficients. The full-width at half-maxima (FWHM) collisional broadening rates of CO₂ by Ar and He, for the R14 (12⁰1 ← 00⁰0) line, have been determined to be 0.161 ± 0.018 cm⁻¹ atm⁻¹ and 0.1823 ± 0.0032 cm⁻¹ atm⁻¹ respectively.