The reaction of HCCO radicals with NO was studied at room temperature by excimer laser photolysis of ketene precursor molecules followed by infrared absorption spectroscopic detection of CO and CO2 product molecules. After quantification of product yields and consideration of secondary chemistry, we obtain the following product branching ratios (1 sigma error bars) at 296 K: 0.12 +/- 0.04 for CO2 + (HCN) and 0.88 +/- 0.04 for CO + (HCNO). In addition, we estimate a relative quantum yield for HCCO production in the 193 nm photolysis of CH2CO to be 0.17 +/- 0.02.