Efficient utilization of pericarp of fruits of Bixa orellanaa major byproduct from the annatto color extraction industrieshas been mentioned here. The lower calorific value (LCV) had been experimentally determined for the postharvest dried pericarp of fruits of B. orellana by ultimate analyses. The experimentally determined LCV is compared with the calculated fuel value index (FVI). The higher LCV of annatto pericarp than the LCV of some plant biomass that are prominently used as a fuel source, viz., tamarind shell, paddy husk, coconut font, paper waste, and groundnut husk, indicates their utility as a potential fuel. Thus, annatto color extraction industries can utilize the major byproductpericarpas a fuel source, and it can also be used as a supplementary source of fuel mainly for third world countries, which can grow this plant primely for the purpose of fuel and with annatto as a secondary benefit in the near future.