Two children from the same family are presented with different clinical symptoms of Mycobacterium tuberculosis infection. A 15-year-old girl presents with a non-tender swelling in her neck and her 9-year-old brother with persistent coughing and fever. Several investigative methods including röntgenology, Mantoux test and microbiological cultures of sputum, gastric, and lymph node aspirates were used in the diagnosis. In both cases, identical strains of M. tuberculosis were isolated from the microbiological culture and anti-tuberculous therapy was initiated. Complete remission of the infection was achieved in both children. The clinical presentation of tuberculosis in children differs from that of adults. This is because extra-pulmonary dissemination of the infection usually takes place before pulmonary symptoms develop. In this article we underline the differences in clinical presentation and the importance of a good history in children suspected of tuberculosis. We also discuss the differences in diagnostic possibilities. The importance of a quick diagnosis and adequate treatment, especially in children, is emphasized in this paper.