Mycobacterial cervical adenitis is an uncommon disease in children in Finland. During 10 years, from 1977–1986, its incidence was of the order of 0.3/year/100 000 children. Of the 12 bacteriologically verified cases, M. avium-intracellulare was isolated in nine, M. malmoense in two and M. tuberculosis in only one case. Neonatal BCG vaccination seemed to protect children against non-tuberculous mycobacterial infection, especially at 1–4 years of age. In Sweden, where neonatal BCG vaccination has been discontinued, the incidence of non-tuberculous mycobacterial adenitis is at least 30 times greater.