To understand the electrocatalytic CO2 reduction of metal carbonyl complexes without "non-innocent" ligands, the electrochemical responses of group 6 M(CO)(6) (M = Cr, Mo, or W) and group 7 M-2(CO)(10) (M = Mn or Re) complexes were examined under Ar and CO2 at a glassy carbon electrode. All of the complexes showed changes in their cyclic voltammograms under CO2 The group 6 hexacarbonyl species show a significant increase in current under CO2 during metal-based reduction, corresponding to catalytic reduction of CO2. Bulk electrolysis experiments with Mo(CO)(6) showed that CO was the primary product. The group 7 dimers showed very little change during metal-based reduction, but return oxidation responses disappeared, indicative of a chemical reaction after exposure to CO2 without catalysis. Addition of H2O, a proton source, to the solutions under CO, decreased the catalytic current of the group 6 carbonyls and had no effect on the responses of the group 7 carbonyls. The group 6 M(CO)(6) species are notable in that that they are effective catalysts without the need for an added "non-innocent" ligand such as 2,2'-bipyridine.