D. immitis [canine heartworm] was found in 8 of 225 (3.6%) red foxes (V. vulpes) collected from fur buyers trappers in Bond, Clinton, DeKalb, Edgar, Ford, Jasper, Moultrie and Richland counties, Illinois. Infections ranged from 1-23 nematodes per fox. The finding of D. immitis in red foxes represents a new host record for the state.