Aim of the work: hypertension is the commonest cardiovascular disorder. Prehypertension in adolescents and young adults is a risk factor for developing hypertension in later years of life. The objective of this study was to determine the prevalence rate and risk factor associated with prehypertension and hypertension in the medical students of Northern Border University in Arar city, Saudi Arabia. Methods: this cross-sectional study included 232 students. The study subjects were selected by systematic random sampling method. This study included 232 medical students (136 male and 96 female). The study period was from 1 March to 31 May 2017. Students were given a predesigned and pretested questionnaire to collect the relevant data. Results:  Fifty (52.1%) of females and 58.8% of males were pre-hypertensive and 1.5% from males were hypertensive. Family history of hypertension was positive in 66.7% of hypertensive or pre-hypertensive students (P<0.05), 18.2% were obese (P<0.05), 9.1% of hypertensive or pre-hypertensive students were diabetic (P>0.05), 31.8% were smokers (P>0.05), 10.6% were drug addicts (P>0.05), 18.2% only performing muscular exercise (P>0.05), 62.1% consume >5g salt /day (P<0.05)and 40.9% of them spent 2-5 hours in front of TV, Computer or mobile (P>0.05). Conclusion: in medical students of the Northern Border University, 52.1% of females and 58.8% of males were pre-hypertensive and 1.5% of males were hypertensive. Risk factors included obesity, family history, sedentary life and excess salt intake. So health-care providers should recognize the increased risk of prehypertension and hypertension and should seek to identify and manage the modifiable risk factors in those students.