It has recently been demonstrated (Hopfgartner et al., 1990; Greibrokk et al., 1992) that the extraction of hydrocarbon biomarkers with supercritical fluids can favourably replace the conventional solvent extraction methods, especially with regard to the amount of sample that is needed (from 50 to 500 mg) and its rapidity. We present here the extraction of pheophytin and pyropheophytin using Freon-22 as the supercritical fluid and compare the results with those obtained by classical solvent extraction. Because the formation of non-polar chlorophyll degradation products (NPCs) seems to play an important role in the early diagenesis of chlorophyll-a, the study of compounds such as pheophytin and pyropheophytin is of some interest to organic geochemistry. The scheme of Treibs and Corwin for the conversion of chlorophyll-a to C₃₂ metalloporphyrin (Filby et al., 1987) does explain neither the formation of pyropheophorbide steryl esters (King et al., 1991; Prowse et al., 1991) nor the presence, in mature sediments, of metalloporphyrins containing more than 32 carbon atoms. We describe here a method to identify in sediments NPCs with more than 32 carbon atoms using supercritical Freon-22 for their extraction.