Hematophagous insects are vectors of diseases that affect hundreds of millions of people worldwide. A common physiological event in the life of these insects is the hydrolysis of host hemoglobin in the digestive tract, leading to a massive release of heme, aknownprooxidantmolecule.Diverseorganisms,frombacteriato plants, express the enzyme heme oxygenase, which catalyzes the oxidative degradation of heme to biliverdin (BV) IX, CO, and iron. Here, we show that the kissing bug Rhodnius prolixus, a vector of Chagas’disease,hasauniqueheme-degradationpathwaywherein heme is first modified by addition of two cysteinylglycine residues beforecleavageoftheporphyrinring,followedbytrimmingofthe dipeptides. Furthermore, in contrast to most known heme oxygenases, which generate BV IX , in this insect, the end product of hemedetoxificationisadicysteinyl-BVIX .Basedontheseresults, we propose a heme metabolizing pathway that includes the identified intermediates produced during modification and cleavage of the heme porphyrin ring.