1. The identification of two novel triterpenoid xanthophylls from Streptococcus faecium UNH 564P is described. 2. Both are aldehydes and were identified as 4,4'-diaponeurosporen-4-al and 4,4'-diapolycopen-4-al. 3. A pathway is presented for the biosynthesis of these and other triterpenoid carotenoids in S. faecium.