In this study we have retrieved the self-broadened widths, self-pressure-induced shifts, and Dicke narrowingcoefficients for 20 R-branch transitions in the 1þ2þ4þ5 band of acetylene. The spectra were recorded usinga three-channel diode laser spectrometer, a temperature-controlled cell of fixed length and a second, roomtemperature cell. The soft collision (Galatry) and hard collision (Rautian) profiles with inclusion of line mixingeffects were used to retrieve the line parameters. We determined the temperature dependencies for linebroadening, shift, and Dicke narrowing coefficients. We performed comparisons between our retrieved lineparameters and published line parameters for acetylene transitions.