The lipid composition of extracts of Cyanophora paradoxa - whole organism and two cell fractions, the endocyanelle and host-mitochondria - has been determined. Endocyanelles were found to contain MGDG, DGDG, PG, S, and PC, while PE and PC are the main lipids of the host-mitochondria. No cardiolipin was detected. This lipid data along with preliminary results on the fatty acids of each lipid are discussed in the context of taxonomic and evolutionary implications.