In Chilean children the incidence of tuberculosis (TB) is low: 2.3/100.000 in younger than 15 years old (2005). This fact may explain that TB diagnosis is sometimes difficult to do in pediatric patients. Our aim was to describe the clinical forms of presentation of TB in children's hospital patients with confirmed TB diagnosis between the years 1989-2005. We carried out this retrospective analysis in 49 patients younger than 15 years old (mean: 5.8 years.); 65.5% of them had a history of contact with an active tuberculosis case. Twenty nine (59.1%) patients were diagnosed as pulmonary TB, 19 of them (65.5%) as primary pulmonary TB and the remainder 10 as post-primary pulmonary TB. Out of the 20 patients with extrapulmonary TB, adenitis was the most frequent (n = 8) followed by pleural effusion (n = 7). Chest x-ray was normal in 10 out of the 49 patients. Major x-ray pathological findings were: primary pulmonary TB 38.7% (n = 19), pleural effusion 14.3% (n = 7), and parenchyma air-space consolidation 10.2% (n = 5). We expect this study would contribute to make a much earlier diagnosis and treatment of TB in children