[Purpose] Insomnia is quite common and it can affect the quality of life of an individual. Students undergo stress due to various academic demands leading to sleeplessness and daytime sleepiness. This study was conducted to investigate the association between physical activity and insomnia among female Saudi students. [Subjects] 62 female students with a mean age of 21 ± 1.5 years took part in a motivational program to increase the number of steps taken per day for three weeks. [Methods] After obtaining subject’s informed consent all the subjects were assessed for insomnia using the insomnia severity index (ISI), They were then given pedometers to calculate the number of steps they took per day. A physical activity log was kept for three weeks. Pre- and post -intervention ISI scores were calculated and correlated with the 3-week physical activity log. [Results] 50% of the subjects had no clinically significant insomnia (NCSI), 42% had sub threshold (STI), and 8% had moderate clinical (MCI) insomnia. There was a moderate negative correlation between physical activity and ISI scores after the 3-week motivation program. [Conclusion] Prevalence of insomnia was common among female Saudi students and increase in physical activity appears to improve the sleep pattern.