The dissociative excitation of CO(a³Π) and other metastable fragments such as O(5S0) produced by electron impact on CO2has been investigated from threshold to 50 ev. The observed threshold for CO(a³Π) production at 11.9 ± 0.5 ev was near the minimum required energy of 11.5 ev. If an isotropic distribution of CO(a³Π) fragments after dissociation was assumed, the cross section for dissociative excitation of CO(a³Π) from CO2was found to be about 3.6 × 10−17cm² at 20 ev, which is 3 times smaller than the maximum cross section for the direct excitation of CO(a³Π) from CO. We also used our time‐of‐flight data to infer a value for the CO(a³Π) dissociative excitation cross section from Ajello's relative cross section measurements, and we obtained a slightly lower value of 1.6 × 10−17cm² at 20 ev. These experiments imply a maximum cross section value of (4.1 ± 3.0) × 10−17cm² at 27 ev. The differential cross section for the dissociative excitation of CO(a³Π) at right angles to the electron beam was found to bedσ/dΩ = (3.0 ± 2.2) ×