AbstractThis chapter reviews the ecology of endophytic fungi associated with the decomposition of leaf litter of tree species and grasses. The occurrence of endophytic fungi on leaf litter; origin and development of early colonizers; succession and persistence in decomposition; and the role of endophytic fungi in the decomposition processes are discussed. This chapter has shown that several of the common endophytic fungi of tree leaves are primarily saprobes, and that they are specifically adapted to colonize and utilize dead host tissue. Future perspectives are given.