Newly emerged bees with damaged wings, bees crawling in front of the hive and unusually severe adult bee mortality were observed in Africanized honey bee colonies in Costa Rica. A large proportion of the adult bee population in most of these colonies was infested with Varroa destructor. Adult bee samples were sent to the Department of Entomology, Penn State University, for virus analysis. This analysis showed the presence of deformed wing virus and Kashmir bee virus. The occurrence of adult bee mortality and the detection of these viruses in Africanized colonies in Costa Rica infested with V. destructor, should be considered as a cause of concern.