Objective: Patients with hypertension often suffer from other comorbidities, resulting in prescriptions of multiple drugs to treat the conditions. Multiple drug treatment is potentially associated with drug interactions. This aim of the study was to assess potential drug interactions in hypertensive patients in Liwa District Hospital. Methods:The design of the study was cross-sectional. The prescriptions for in-patients with essential hypertension in the Internal Medicine Unit in Liwa District Hospital during April-December 2012 were collected. Potential drug interactions were analyzed with the Drug Interaction Facts version 4.0, and classified into minor, significant, and serious.Results: A total of 60 hypertensive patients were included. They were prescribed 265 prescriptions, with a median total of 6 (range 1-21) drugs prescribed per prescription. There were 1616 potential drug interactions, with 6 (1-31) potential interactions per prescription. Most interactions (75.6%) were classified as significant. Serious potential interactions were most common in the combinations of diltiazem-amlodipine and spironolactone-potassium chloride, while significant potential interaction may occur most often with the combinations of calcium chloride-amlodipine and bisoprolol-amlodipine. Conclusion:Numerous potential drug interactions might occur in hypertensive patients, and most interactions were significant in severity. The largest proportion of the interactions occurred between antihypertensive agents and other drugs.