Back ground: Diabetes mellitus (DM) is a group of common metabolic disorders that share the phenotype of hyperglycemia. Half century ago hydrochlorothiazide has been associated with a diagnosis of diabetes in hypertension treatment containing hydrochlorothiazide during long term therapy. This explained by association between glucose, potassium, and hydrochlorothiazide induced hyperglycemias and plasma insulin level. The objective of this study was to assess the problem associated with use of hydrochlorothiazide among adult diabetic patient in diabetic clinic of AHMC. Methodology: A cross sectional study was carried out by reviewing patient information sheet and physician diagnosis card with a period from March, 25-May, 28, 2014. Data was collected from patient information sheet and physician diagnosis card by using check list and collected data was analyzing by using SPSS-20.