The purpose of the study was to assess the effect of aerobic exercises on undergraduate male students of various colleges of University of Delhi. A total number of 75 undergraduate male students were taken as the subjects of this study. The age of the selected subjects was above 17 years of age. The Perceived Stress Scale (PSS) was employed as a questionnaire. Scoring was done according to the instructions given in the test manual of the checklist. The descriptive statistics was used for summarizing numerical data. To compare the stress paired samples t test was applied. The statistical analysis was performed with the help of SPSS. The result of the study indicated that there is a significant difference in stress of undergraduate male students. The Post Stress has lower Mean and SD value then Pre Stress.