The conjugated double bonds in the characteristic polyene chain of carotenoids make these compounds susceptible to geometrical isomerization. The separation of these isomers and their identification is of utmost importance since the different isomers of a carotenoid may present different physicochemical properties, stability, bioavailability, and bioactivity. This chapter describes how to separate and tentatively identify geometrical isomers of carotenoids by liquid chromatography, providing multiple chromatograms and spectra useful for this purpose. In addition, some recommendations for the quantification of isomers are also detailed.