The product distribution of the HCCO + NO reaction is examined theoretically over an extended temperature range, using RRKM-master equation analyses incorporating the effect of internal rotations on the state densities. The potential energy surface was characterized at the B3LYP-DFT/6-311++G(d,p) and CCSD(T)/6-31G(d,p) levels of theory, combined with high-level single point CCSD(T)/6-311++G(2d,p) calculations. The only reaction products of importance were found to be HCNO+CO and HCN+CO2, where the predicted CO2 yield can be expressed as alpha (T) = 0.0652 + 0.220 exp(-T/917.9 K), for T = 300-2500 K. The predicted product distribution is in agreement with the available experimental values.