Subcutaneous vaccination of fancy and racing pigeons with inactivated oil-based vaccines protects against all clinical manifestations caused by the Paramyxovirus type 1. Correct application of the vaccine may occasionally result in the development of granulomas or abscess-like lesions on the site of vaccine application. Although protected against disease as proven by challenge experiments, a variable proportion of vaccinated pigeons do not react with the formation of detectable serum antibodies. The pathogenesis of granuloma and abscess-like lesion developments and the failure to form humoral antibodies are presently not understood. Questions relating to legal liability of vaccinating veterinarians are briefly discussed.