Abstract: The tuberkulin test has been the traditional method for detection of infection with tubercle bacilli. Epidemiologists have used it extensively for assessment of tuberculosis situation in different communities. In clinical practice, it is used to find out the presence or absence of tuberculous infection. This aids in the differential diagnosis of tuberkulosis among children and to decide about administration of chemoprophylaxis. The tuberkulin skin test is one of the few investigations dating from the 19th century that is still widely used. It was developed by Koch in 1890, but the intradermal technique currently in use was described by Mantoux in 1912. After such a long history it is surprising that the interpretation of the test remains controversial. The tuberkulin most widely used is purified protein derivative (PPD), which is derived from cultures of Mycobacterium tuberculosis. Although tuberkulin test is widely used for detection of tuberculous infection among children, there is no clear understanding about its performance and interpretation. This article has been written with the purpose of elucidating the performance and interpretation of standard tuberkulin test.