The thermal decompositions of 2-azidoethanol and 2-azidoethyl acetate have been studied by matrix isolation infrared spectroscopy and real-time ultraviolet photoelectron spectroscopy. The products that were detected in a flow system at different temperatures (CH2NH, H2CO, N-2, CO, and HCN from N3CH2CH2OH and C2H4, CH2NH, HCN, CO2, and N-2 from N3CH2COOCH2CH3) allowed mechanisms for decomposition to be proposed. The experimental evidence obtained is consistent with 2-azidoethyl actetate decomposing via a concerted mechanism, similar to that found previously for azidoacetic acid, whereas the 2-azidoethanol decomposition is consistent with a stepwise decomposition mechanism as observed previously for azidoacetone.