A new detailed kinetic mechanism for formaldehyde and methanol combustion has been developed using the Konnov mechanism, version 0.6, as a starting point. In total, 82 reactions of the formaldehyde and methanol subsets were reviewed and updated using a systematic approach. Rate constants were selected based on thorough evaluation of available experimental and theoretical data. No modifications of the rate constants were performed. The mechanism was validated over a wide range of experimental conditions and devices, including shock tube and flow reactors and burner stabilized and freely propagating flames. An overall good agreement with experimental data was seen. Simulated shock tube pyrolysis and flow reactor oxidation was generally in satisfying agreement to the experimental results, and the new mechanism showed a significant improvement in predicting the laminar burning velocity of methanol.