BAC libraries are essential tools for assisting crop genome analysis. Various projects conducted at Cirad are resting on libraries made available by the Clemson University Genomics Institute. Given the rapid extension of genomics projects on tropical crops, we have begun the creation of novel BAC library resources for a number of tropical species. Our efforts are now focused on the construction of a banana (Musa acuminata) BAC library with Embrapa and Inibap. This will represent the starting point for molecular cytogenetic analyses aimed at identifying and localising translocation breakpoints and integration pattern of the banana streak virus. It will also assist projects aimed at understanding the inheritance of desirable traits for more efficient banana breeding. Furthermore, preliminary feasibility tests for the construction of BAC libraries are being carried out in rubber tree (Hevea brasiliensis), cacao (Theobroma cacao) and oil palm (Elais guineensis).