Background: In the past ten years, there has been a considerable rise in the usage of smartphones, and it has been noted that students use mobile phones for prolonged hours and thus they may commonly experience hand pain. Prolonged usage of smartphones may lead to daily-life disturbances including neck and wrist disorders, such as carpal tunnel syndrome & grip weakness . Purpose: To explore the effect of prolonged smartphone usage on hand grip strength and median nerve conduction velocity, and the association between smartphone usage duration and hand-grip strength and nerve conduction velocity among female medical students in Umm Al-Qura University . Methods: A 70 female subjects from umm Al-Qura University (UQU), their ages ranged from 19-25 years, volunteered to participate in the study. Data was conducted using a pre-experiment scale of smart phone addiction scale – short version (SAS-SV) questionnaire for collecting demographic data about the participants determining the smartphone usage. Participants were briefly examined for hand-grip strength measurement was performed using a hand-held dynamometer and median nerve conduction velocity measurement was performed using electromyography studies through one assessment session Data analysis: By using descriptive statistics for demographic data of the participants. The student t-test to compare between mean groups and bivariate correlation to assess the relationship between smartphone usage and hand-grip strength and median nerve conduction velocity, with P-value below 0.05 was assumed to be significant. All data were entered and analyzed through statistical package for social sciences SPSS version 16 Results: There was significant difference (P-value < 0.05) in the hand grip and median nerve conduction velocity between addiction and non-addiction group with a low strength significant (r = 0.33, p = 0.005) inverse relationship between smartphone usage duration and hand-grip strength and a non-significant relationship between smartphone usage duration and median nerve conduction velocity with little or no correlation (r = 0.08, p = 0.524). Conclusion: Prolonged use of smartphones was related to weaker hand-grip in medical female students of UQU who use smartphones for more than 4 hours, while there was a normal value of median nerve conduction velocity in both smartphones addicted and non-addicted students.