This is the first complete assessment of the ectoparasite fauna on phyllostomid bats in a shaded coffee plantation in Mexico. The study was carried out at Finca San Carlos, in the municipality of Tapachula, southeastern Chiapas, Mexico. The bats were captured over three consecutive nights every month, from December 2005 to November 2006, using four mist nets. We captured 192 phyllostomid bats, representing 18 species, upon which 1,971 ectoparasites, belonging to 11 families and 65 species, were found. We found that 160 of the 192 captured bats were hosts to ectoparasites, giving an infestation prevalence of 83.3%. Of the 65 ectoparasitic species, 14 were classified as monoxenous and 17 as stenoxenous. More ectoparasites were recorded in the dry season (n = 1,439) than the wet season (n = 532), and we recorded some families of ectoparasite on particular areas of the bat body. An ordination of bat species, based on their ectoparasitic species community structure, formed groups at the subfamily level or lower taxonomic categories. We suggest that the close ectoparasite-host relationships could be examined as an additional tool to elucidate the taxonomic relationships between the hosts.