Eight new coumarins were isolated from the fruits of Seseli devenyense Simonkai. Their structures were established from NMR and mass data and their absolute configurations from chemical degradation correlation reactions. The new structures are the decanoic and dodecanoic esters of (+)-lomatin (3, 4), the decanoates of (+)-cis-khellactone at positions 4' (5) and 3' (6) as well as the 2'S epimer of 8-(2,3-dihydroxy-3-methylbutyl)-7-hydroxychromen-2-one (7) named devenyol, its two O-monoglucosides at positions 3' and 7 named devenyosides A (8) and B (9), and the corresponding 3'- and 7-O-diglucoside named devenyoside C (10). This plant is an interesting example of stereochemical diversity based on biodiversity given that other members of the Apiaceae family produce exclusively the 2'R epimers of compounds 7-9.