Aim: The aim of the present study was to determine the effect of acute bout of moderate exercise in cognitive processing in young women during different phases of menstrual cycle. Methods: It was a cross-sectional observational study conducted on 50 young, normally menstruating women with normal auditory capability. Before the commencement of the study ethical approval was taken from the ethical committee of the institute and informed consent was taken from the patient. The study was conducted in a clinical physiology laboratory. Results: There were significant changes in all cardiovascular parameters in post-exercise session in comparison to pre-exercise session in both phases of menstrual cycle. The P300 latency showed significant decrease in postexercise session when recorded at Cz as well as Pz position in both phases of menstrual cycle. However, P300 latency recorded at Fz position displayed no significant change at post- exercise session in comparison to pre-exercise session during both phases of menstrual cycle. Conclusion: The present study concluded that an acute bout of moderate exercise caused significant decrease in latency of P300 ERP in the participants during both phases of menstrual cycle. That means even acute bout of moderate exercise enhances cognitive functioning of the individual.