This study focused on devising a method for accurately analyzing the reaction products derived from the upgrading of fats and oils to hydrocarbons. A single method capable of identifying and quantifying all the major constituents commonly found in samples of interest was developed, including the triglycerides and fatty acids constituting the feed, the alkanes resulting from the deoxygenation of the feed, and other intermediates and byproducts, such as alkenes, alcohols, aldehydes, and esters. A standard GC-FID-based method for the analysis of hydrocarbon mixtures (ASTM D 2887) was used as a starting point, and through a number of modifications to both hardware and programming, a method capable of affording a single chromatogram in which all the aforementioned components are fully eluted and well-resolved was developed. In addition to its reliability and its versatility, this approach is relatively fast, straightforward, and inexpensive, as no sample derivatization prior to analysis is required.