Pulmonary tuberculosis (T.B.) is a disease which causes chronic sickness and deaths.   It has a high prevalence in developing Asian and African countries. Since the past two decades, there has been a resurgence of T.B in affluent developed countries, due to immune depressive conditions like HIV/AIDS, malignancies, uncontrolled diabetes, e.t.c. World T.B. day observed on 24th March is for consideration of the grave worldwide health threat posed by T.B.The lungs get infected via inhalation of drops containing T.B. germs. These drops are expelled in the atmosphere by coughing or talking by an affected person.  One third of the world’s population is said to be infected by T.B. germs, but   not all develop the disease. Development of the disease depends on the amount of bacilli inhaled and resistance of the affected person.  Once the germs   enter the body, body’s immune system tends to contain the infection.  But if the person is exposed another   time, or his immunity goes down for any reason, he can develop   disease as the microbes lying dormant get activated.  Pulmonary T.B., can affect a person of any gender, age or socio economic status. But mostly it is the world’s poor who are more affected. Overcrowding , malnutrition, immune deficiency states are some of the risk factors which make a person more vulnerable to T.B. Occupations which involve constant exposure to smoke or dust of any kind,  eg., as in coal miners,  increase susceptibility to develop T.B. of the lungs. Smokers are yet another group of people at risk to have pulmonary T.B. as chronic   smoking damages the protective layer of respiratory passages. Chronic cough with or without bloody sputum,    night fever and sweating, loss of appetite and   weight, are characteristic features of pulmonary T.B. If untreated, the infection can extend and damage the entire lung.  It can spread to coverings of the lung. The infection can spread   directly or via blood stream to various other parts of the body, affecting them, resulting in extra pulmonary T.B. Intestines, back bone, heart, any part can be affected by T.B.A person suffers not only at time of infection but also from the sequel. If the lung parenchyma gets damaged due to T.B. even after clearing of the infection, he can suffer from chronic   breathlessness and his stamina is reduced. Healing of a tubercular patch   occurs   by fibrosis, where elasticity of the lung is damaged, thus reducing   efficiency of the lung.Diagnosis of pulmonary T.B. is suspected when a person has the typical symptoms. It is confirmed by demonstration of the mycobacterium in sputum.  X-ray of the chest and Mantoux test (intradermal test of sensitivity to tubercular antigen) also aid in diagnosis. Problem arises during treatment of tuberculosis. Good treatment to ensure complete eradication of the mycobacterium is for 6 months. Many persons start feeling good after one to 2 months and abandon the drugs on their own. These people still harbor the germs and can infect other people with whom they come in contact. When treatment is restarted, the microbes become   resistance to the drugs used. Multidrug   resistant T.B. , has become a cause for concern, globally.Adverse drug reactions are yet another reason for people to abandon the treatment. Prevention of T.B. is of utmost importance.  People should know the risk of spitting in public and avoid it. While coughing or sneezing, a person should   cover his mouth to prevent the droplets from being dispersed in the environment.  Houses and work places should have adequate sun light and cross ventilation to prevent   accumulation of germs of any kind. Screening for T.B. is must for people in contact with T.B. cases or in high risk groups like prisoners or HIV patients.Once somebody has pulmonary T.B. it is essential to take treatment for the entire duration. Good compliance with treatment helps in curing the affected person and also minimizes the risk of spread of infection to others.