The research aimed to determine the effect of backpack design on posture, heart rate, and muscular discomfort among female university students. A randomized control trial was used, the participants were the frameless backpack (n=25) and the internal frame backpack (n=25). The participants loaded the backpack with 15% of their body weight. Heart rate was measured by a polar heart rate monitor and discomfort scores were measured by VAS scale. The craniovertebral angle and trunk angle were measured. An analysis of variance was used for statistical analysis to evaluate the effect of backpack design on each parameter. There was a significant difference in craniovertebal angle though no significant difference was found in trunk angle between the backpacks, and the internal frame backpack had significantly increased in heart rate. A significant increase of discomfort was also found only at the neck region when carrying the frameless backpack. The internal frame backpack gave the students more comfortable only mostly at the neck region when compared to the frameless backpack. Moreover, the internal frame backpack had increased the heart rate. Also, the application of this study was to advise the young adult to choose a suitable backpack for daily activity.