Dissociative electron attachment rate constants have been measured for Cr(CO)6 under thermal conditions, 296–400 K, yielding Cr(CO)5− product. At 296 K, 2.92 ± 0.70 cm3 s−1 was measured and a small decrease with temperature was observed (2.72 ± 0.70 cm3 s−1 at 400 K). We additionally determined the cation products of Ar+ reacting with Cr(CO)6.