Descriptions in the medical literature of human immunodeficiency virus type 1 (HIV-1) in children with tuberculosis (TB) are scanty. This study determined the seroprevalence of HIV-1 in 237 hospitalized children between the ages of 1 month and 14 years with a clinical diagnosis of TB (125 males and 112 females) and in 242 control children (149 males and 93 females). The overall HIV-1 seroprevalence rate in patients with TB was 37% (88 of 237) compared with 10.7% (26 of 242) among the control group (P < 0.00001: odds ratio 5.37, 95% confidence interval = 3.21 < 5.37 < 9.47). HIV-1 seropositivity in children with TB ranged from 53% (31 of 58) in the 12- to 18-month age group to 14% (9 of 61) in the 10- to 14-year-olds. The risk of TB attributable to HIV infection was 29%. The predominant clinical presentation in both seronegative (84.6%) and seropositive (89.7%) groups was that of pulmonary TB and there were no significant differences in clinical presentation between the two groups of patients. Only 54.8% of the patients attended follow-up clinics regularly whereas 32% were lost to follow-up within 3 months. Bacillus Calmette-Guérin vaccination coverage was 87.3% among TB patients and 90.5% in the controls. No significant differences in B. Calmette-Guérin vaccination rates between the seronegative and seropositive children were seen. Coinfection with HIV and TB in children is now one of the major public health problems in Zambian children.