Endophytic fungi were identified from different parts of the medicinal parasitic mistletoe Cladocolea micrantha and from its host Anacardium occidentale, suggesting a strict host-parasite relationship. Eight fungal endophytes were iso- lated and morphologically characterized. The ascomycete Guignardia mangiferae and strains of Mycelia sterilia were prevalent in the isolations. The unequivocal identification of Guignardia mangiferae at a probabilistic degree close to 100% was carried out by DNA extraction followed by PCR analyses of the ITS-1 and ITS-2 regions and comparison of the genetic sequence with the NCBI database.