The changes in carotenoid content and profile were studied in oil palm (E. guineensis) mesocarp at various stages of development. Spectrophotometric analysis showed that chlorophyll synthesis predominates in the young fruits but it then shifts strongly to carotenoids as the fruit ripens. The major carotenoids in the oil from ripe fruits are α- and β-carotenes. A very wide variation in total carotenoid content was observed in various E. guineensis genotypes. High performance liquid chromatography (HPLC) analysis using both C18 and C30 stationary phases showed the C30 phase to be superior in separating the cis– and trans- isomers of both α- and β-carotenes and resolving other components. Lycopene was not detected in at all. Incorporation studies were carried out with various ¹⁴C-labelled substrates – acetate, glyceraldehyde-3-phosphate (G3P), isopentenyl, pyrophosphate (IPP), mevalonic acid (MVA) and pyruvate. IPP was the most incorporated showing it to be a major intermediate in carotenoid synthesis in the oil palm. There was also considerable incorporation of acetate, IPP and MVA into α- and β-carotenes. G3P and pyruvate were not incorporated into a- and ß-carotenes suggesting that carotenoid synthesis in the oil palm follows the acetate/ mevalonate pathway.