Stress leads to many changes in the body with some being advantageous while others are harmful. Findings of studies on the effects of acute stress in the form of academic final exams on the body are contradictory. This study determined the effects of exam stress on the immune system in 41 randomly chosen healthy Saudi female university students. All subjects filled a consent form and a questionnaire to categorize them into high and low-stress level groups. Blood samples were collected from the subjects on a day without final exams and later on a day of a final exam to determine the total and differential white blood cells (WBC) counts, and concentrations of cortisol and all immunoglobulin types. Results show that all subjects and subjects that felt a low-stress level had increased mean WBC, neutrophils, lymphocytes, and basophils cell counts; increased mean IgM and cortisol concentrations; decreased mean IgG concentration; and no change in the IgA, IgD, IgE concentrations for the exam period compared to the no exam period. Students that felt a high level of stress on the exam day, compared to the no exam period, had increased mean WBC and neutrophils cell counts, while cortisol and all antibodies concentrations were not different. Therefore, in conclusion, acute stress in the form of exam stress led to some enhancement of innate and acquired immunities, and some effects on humoral immunity and these changes occurred alongside increased cortisol levels. Additionally, subjects that felt a high-stress level showed fewer effects on innate and acquired immunities and no effects on humoral immunity compared to those who felt a low-stress level.