The heat of formation of CF2O has been calculated at high levels of ab initio molecular orbital theory. The best values were obtained by extrapolating CCSD(T) energies obtained from the correlation consistent basis sets, up through augmented quadruple-zeta, to the complete basis set limit. Core/valence corrections were obtained from basis sets designed to recover such effects. Zero-point energies were taken from experiment, and missing values were calculated at the MP2/cc-pVTZ level and scaled to approximate experimental values. The calculated Delta H-f(degrees) values are CF = -58.2 +/- 0.5 kcal/mol, CF2 = -46.6 +/- 0.7 kcal/mol, FCO = -44.1 +/- 0.5 kcal/mol, and CF2O = -145.2 +/- 0.8 kcal/mol.