Introduction: Selenium (Se) is a trace element that has role as an antioxidant in acute stress like; systemic inflammatory responses or trauma. Literature shows positive correlation between low serum Se levels and bronchial asthma. Aim: To determine the level of serum Selenium (Se) in bronchial asthma and to compare the Se levels with the age-matched control group without asthma. Materials and Methods: This cross-sectional study was conducted at the Departments of Physiology and Pulmonary Medicine of a Government Tertiary-care Hospital in Kerala, from November 2021 to March 2022. A total of 24 patients of Bronchial Asthma, between 20-55 years of age and 24 age-matched controls were selected. Serum Se levels were estimated in cases and controls, using Atomic Absorption Spectrometer (AAS). Statistical analysis of the data was done using unpaired sample t-test and correlation was tested with Chi-square test, using Statistical Package for Social Sciences (SPSS) version 27.0. Results: Serum Se levels of 24 patients with Bronchial asthma, aged between 25-55 years and the Se levels in the age-matched controls were obtained. The mean Se level in the study group was (67.21±39.57 ngm/L) significantly lower (p-value was 0.0001) than that of the control (108.38±19.22 ngm/L). The mean age was 39 years±10.8 years. Out of them, 40% were females and the remaining 60% were males. The severity of Asthma ranged between mild persistent asthma to moderate asthma. And the mean duration of asthma was 5.59 years. Conclusion: Serum Se in adult bronchial asthma patients aged between 20 years to 55 years, with mild to moderate severity was significantly lower than that in the control group