Morbidity caused by tuberculosis was determined in a cohort of 9,328 refugees from Southeast Asia during the first 5 yr after their immigration to the United States. The entire cohort was screened at the time of entry, and isoniazid preventive therapy was offered according to ATS-CDC guidelines. During the period of study, 25 cases of tuberculosis were reported from the cohort. The 5-yr cumulative incidence of tuberculosis (26.8 cases per 10,000 in the entire cohort) was greatest in tuberculin-positive refugees who had abnormal screening chest roentgenograms (324.3 cases per 10,000) and least in those with nonsignificant tuberculin reactions (5.0 cases per 10,000). The annual incidence of tuberculosis in the cohort decreased from an estimated 30.6 cases per 10,000 at the time of immigration to less than 5 cases per 10,000 during the fourth and fifth years. The prevalence of resistance to isoniazid was greater in culture-positive cases arising after immigration (7 of 22, 32%) than in those diagnosed at the time of immigration (5 of 36, 14%), probably because of a reduction in isoniazid-susceptible cases by isoniazid preventive therapy. Currently recommended screening and preventive services may be favorably impacting tuberculosis morbidity in newly arriving refugees from Southeast Asia.