The purpose of the present research was to examine the effect of one bout of exhaustive aerobic exercise with two different intensities on levels of serum MDA in male smokers. For this purpose, 12 male smokers (age: 22.08 ±1.31 years, percent of body fat: 17.26 ±4.92% and body mass index: 23.21±2.96 kg/m2) were voluntarily selected and randomly participated in a crossover design in three situations of control, exhaustive aerobic exercise at 70%-75% intensity of maximal heart rate and exhaustive aerobic exercise at 90%-95% intensity of maximal heart rate. Blood samples were collected before and immediately after the exercise. Malondialdehyde level was determined with method of ELISA. The data were analyzed using one-way ANOVA and dependent t tests. The results indicated that MDA in two experimental groups was significantly higher than the control group. Also, the comparison of the two experimental groups showed that aerobic exercise at 90%-95% intensity of maximal heart rate increased serum MDA more than aerobic exercise at 70%-75% intensity. It is suggested that smokers perform the physical activities with moderate intensity (70%-75% intensity of maximal heart rate) because oxidative stress is produced in these activities less than activities with higher intensity.