Canine distemper virus (CDV) has a wide host spectrum, and during the past years, distemper has been observed in species that were previously not considered to be susceptible. In this study, we investigated the prevalence of CDV-specific antibodies in red foxes (Vulpes vulpes) sampled between May and November 1997. About 9 to 13% of the Luxembourg red fox population is positive for antibodies against CDV. Thus a sizeable proportion of red foxes has been exposed to CDV in the wild. The significance of CDV in red foxes is discussed.