Tuberculosis is an infectious disease caused by mycobacteria which belongs to the genus Mycobacterium and the family Mycobacteriaceae. Although tuberculosis is known for thousands of years, it is still an important diagnostic and therapeutic problem throughout the world, especially in poorer countries. Still correct diagnosis of active infection with M. tuberculosis causes many difficulties. The paper presents the most relevant issues concerning the diagnosis and treatment of tuberculosis, to be reflected in daily practice.