Background: Hypertension is the most serious health problems in the world. Though modern medicine can improve the well-being, its benefit can be compromised by drugrelated problems (DTPs). Objective: The objective of the study is to determine both type and number of drug related problems and factors affecting it in Ambo General Hospital. Methods: A hospital based cross – sectional study was conducted. All patients who had contact time during the data collection were included. Trained data collectors collected the data. Result and conclusion: A total of 151 ambulatory hypertensive patients were found during data collection period in Ambo general Hospital. A maximum of 200 drug therapy problems were found. The mean DTP was 1.32 + 0.47. The most common DTP was indication type problems. The maximum number of DTPs was three. None of the independent variable is associated with both presence and number of Drug Therapy Problem.