Methods for the detection of two strains of avian encephalomyelitis virus (AEV) in chick embryo brain cell cultures and chickens were compared. It was found that the agar gel precipitin test (AGPT) and the enzyme-linked immunosorbent assay (ELISA) carried out on the serum of inoculated chickens were more sensitive than either the indirect fluorescent antibody test in cell cultures or the detection of clinical signs in chicks. On the basis of results obtained in this experiment the effects were then determined of routes and time of inoculation of chickens on the detection of AEV. It was found that birds infected at two weeks old produced higher antibody titres than one-day-old birds and the AGPT and ELISA detected comparable levels of antibody in them. It was recommended that the tests to detect the presence of AEV as a contaminant of vaccines be replaced by a serological test carried out on chicks inoculated intramuscularly at two weeks old.