Deutonymphs of four species of Parasitellus were found phoretic on Danish bumblebees. On overwintered queens of Bombus terrestris L. and B. lucorum L., nymphs of Parasitellus jucorum (De Geer) constituted 17,9-23,4 % of the Parasitel!us fauna; correspondingly Parasitellus talparum (Oudem.) Hyatt constituted 19,7-21,6 %, Parasitellus ignotus (Vitzthum) Hyatt 45,5-48,4 %, and Parasitel! us crinitus (Oudem.) Hyatt constituted 11,5-12,1 % of the phoretic Parasitellus fauna of the queens. On worker bumblebees (B. terrestris and B. lucorum) ali four Parasitellus species occured in much smaller numbers and Jess frequently than on queens. Only P. jucorumwas found on drones. Statistical analysis of association between presence of the four species of mites on potential nestfounding queens, showed significant positive association between each of the species P. talparum, P. ignotus and P. crinitus. Significant negative association was found between infection by the nematode Sphaerularia bombi Dufour and presence of deutonymphs on queens.