We describe measurements demonstrating laser cooling of an atomic gas by means of collisional redistribution of radiation. The experiment uses rubidium atoms in the presence of several hundred bar of argon buffer gas pressure. Frequent collisions in the dense gas transiently shift a far-red detuned optical field into resonance, while spontaneous emission occurs close to the unperturbed atomic transition frequency. Evidence for the cooling is obtained via both thermographic imaging and thermographic deflection spectroscopy. The cooled gas has a density above 1021 atoms/cm3, yielding evidence for the laser cooling of a macroscopic ensemble of gas atoms.