Abstract: These days, Mycobacterium tuberculosis (Mtb) bacil is estimated to have infected one third of the world's population. World Health Organization (WHO) data shows that in 2011 there were 8.7 million case of tuberculosis (TB) or equivalent to 125 cases per 100.000 of the world’s population. Some studies have been done to understand the role of certain genes toward the susceptibility of TB patients, most of those studies focused on genes that are involved in signal pathway of interferon gamma (IFN-γ). Interferon gamma is one of the cytokine that has a role in pathogenesis of pulmonary tuberculosis. Single nucleotide polymorphism of IFN-γ at +874 T/A position in the first intron is reported to have association with pulmonary TB in different population. The aim of this study is to investigate the genetic variation of IFN-γ in +874 T/A and its relation with IFN-γ plasma level in pulmonary tuberculosis patients. The study’s method is cross sectional. Blood sample was taken from the veins of new AFB (Acid-Fast Bacillus) positive tuberculosis patients. Purification examination of Deoxyribonucleic Acid (DNA) and Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) for determining the genotype of IFN-γ genes and the level of IFN-γ is measured using Enzyme Linked Analysis Techniques Immunosorbent Assay (ELISA). The data is presented using tables and pictures. There is a significant association between IFN-γ +874T/A genetic variations with the plasma level of IFN-γ. There is a domination of IFN-γ +874T/A heterozygote genotype found in pulmonary TB population with positive +1of AFB and far advanced lesion on chest x-ray.