Genetic studies indicate to the importance of individual genetic diversity on predictor of mortality. Furthermore, Single Nucleotide Polymorphisms can be used to identify disease-causing genes in humans and they can be either neutral or deleterious. Human Tumor necrosis factor-α is a well-known inflammation factor that is closely associated with sepsis and severe sepsis. Our objective was to evaluate the association of TNF-α -308 G/A promoter polymorphism with dependency to severity of pneumonia. Respiratory diseases, especially pneumonia, is the major cause of mortality and morbidity in Ulaanbaatar, Mongolia and the leading causes of pediatric hospitalization. We collected blood samples from 101 pediatric patients of the age group between "new born" and "school aged", who were treated and diagnosed with pneumonia in February 2019 and 2020, the pneumonia season in the country. Genomic DNA was extracted and performed by PCR-RFLP method to detect the presence of SNPs. The studies showed that the TNF-α -308 G/A polymorphism among pediatric patients, genotype G;G was 73.27%, genotype A;G was 22.77%, and genotype A;A was 3.96%. Our study demonstrated disassociation of TNF-α -308 G/A polymorphism with pneumonia severity in population.