In Finland, the situation with regard to tuberculosis has been constan
tly improving during recent gears, and the WHO criteria for a low inci
dence country (10/100,000) are presently satisfied. In contrast, the n
umber of clinical specimens yielding atypical mycobacteria by isolatio
n has rapidly increased. Organisms belonging in Mycobacterium avium-in
tracellulare complex dominate among the isolated species.