The structure of premixed ethyl butanoate/O2/Ar flames stabilized on a flat burner at atmospheric pressure was studied by molecular beam mass spectrometry. Mole fraction profiles of the reactants, stable products, and major intermediates and temperature profiles were obtained in flames of stoichiometric (φ = 1) and rich (φ = 1.5) combustible mixtures. Experimental data are analyzed and compared with previously obtained experimental and numerical data for methyl pentanoate flames. The structure of ethyl butanoate flames is simulated using a detailed literature chemical-kinetic mechanism for the oxidation of fatty acid esters. The experimental profiles are compared with the simulated ones, and the conversion pathways of ethyl butanoate are analyzed. Based on a comparative analysis of experimental and simulated data, the main shortcomings of the model presented in the literature are identified and possible ways are proposed to improve the model. The decomposition of ethyl butanoate and methyl pentanoate are discussed based on an analysis of their conversion pathways; similarities and characteristic differences between their oxidation processes due to the structural differences of the molecules of the fuels are outlined.