Abstract Background: In today's society, women have a lot of tasks at work, study, family, social events and this coupled with the use of large and heavy shoulder bags put them at a particular risk of injuries in the shoulder complex. Aim of Study: This study aimed to compare between carrying a unilateral shoulder bag on the dominant versus non-dominant side on upper trapezius muscle fatigue, strength and shoulder function. Subjects and Methods: One hundred and twenty healthy females right handed with age ranging from 20-59 were randomly assigned into 2 equal blocked groups. The outcome measures included, upper trapezius fatigue & strength (via hand-held dynamometer) as well as shoulder function (via simple shoulder test). Both groups walked on a treadmill for 5 minutes with speed 1.1m/s (group A) was carried the bag on the dominant side & (group B) was carried the bag on the non-dominant side. The outcome measures were collected pre & post-test for the dominant side (group A) & the non-dominant side (group B). Results: The results of this study revealed that there were no significant differences in terms of fatigue & function between pre & post measurments, but there was a significant difference in upper trapezius muscle strength for both groups. However, there were no significant differences between the dominant & non-dominant sides in terms of fatigue, strength & function. Conclusion: Our results revealed that there were no significant differences when carrying a shoulder bag on the dominant & non-dominant side on upper trapezius fatigue, strength & shoulder function.