Extrapulmonary organ involvement in human immunodefiaency virus (HIV)-infected patients with pulmonary tuberculosis (TB) is reported to be 26%, however, the clinical predictors of extrapulmonary involvement in pulmonary TB patients has not been reported yet. We tried to determine the clinical predictors of presence of extrapulmonary involvement in patients with pulmonary TB. Cross-sectional study was performed including all adult patients with culture-proven pulmonary TB diagnosed between January 1, 2004 and July 30, 2006, at a tertiary referral hospital in South Korea. The presence of extra-pulmonary TB involvement was diagnosed based on bacteriological, pathological, or clinical evidence. Among 320 patients with a culture-proven pulmonary TB, 40 had extrapulmonary involvement. Patients with bilateral lung involvement were more likely to have extrapulmonary involvement, with an adjusted odds ratio (OR) of 4.21 (95% confidence interval [CI], 1.82-9.72), while patients older than 60 yr (adjusted OR, 0.27; 95% CI, 0.08-0.89), patients with cavitary lesions (adjusted OR, 0.37; 95% CI, 0.16-0.84), and with higher levels of serum albumin (adjusted OR, 0.45; 95% CI, 0.25-0.78) had less frequent involvement. Clinicians should be aware of the possibility of extrapulmonary involvement in TB patients with bilateral lung involvement without cavity formation or lower levels of serum albumin.