Objective: The objective of the study is to review the isolation of No
ntuberculous mycobacteria in King Khalid National Guard Hospital, a Re
ferral Hospital in Jeddah, Kingdom of Saudi Arabia, population between
1993 and 1995 and to determine their contribution to lung disease. Me
thods: The medical records of all patients in whom Nontuberculous myco
bacteria were isolated between 1993 and 1995 were reviewed. The criter
ia used for the diagnosis of Nontuberculous mycobacteria disease or co
lonisation were those recommended by the American Thoracic Society. Re
sults: Mycobacterium species were isolated from 217 patients. One hund
red and thirty nine (64.1%) were Mycobacterium tuberculosis. The respi
ratory tract was the most frequent source of isolation of Nontuberculo
us mycobacteria, 120/139 (86.3%). The most common species isolated in
all specimens were Mycobacterium avium intracellulare, 81/139 (58.3%)
while M. fortuitum occurred in 43/139 (30.9%). Of the 120 patients wit
h a pulmonary isolate, 45 (37.5%) had underlying chronic lung disease.
Conclusion: The most prevalent species of Nontuberculous mycobacteria
in our hospital population are M. avium intracellular and M. fortuitu
m, and both frequently associated with chronic lung disease. Physician
s need to be conversant with the diagnosis and subtle clinical feature
s of Nontuberculous mycobacteria disease.