Backgroud: Hypertension is one of the most common worldwide health problems, medication adherence is a major public health concern and leads to considerable morbidity, mortality, and healthcare costs.  Objective of Study: The main objective of this study was to an Investigating Medication Adherence and Illness Perception Among Patients with Hypertension in Al-Nasiriyah Teaching Hospital.  Method: A quantitative descriptive cross-sectional design was performed among 424 adult hypertensive patients attending hypertension clinics in Al-Nasiriyah Teaching Hospital in Al-Nasiriyah, southern Iraq. over a period of three months from April 6th, 2022, to June 29th, 2022. study requirements were selected using a convenience sampling method, were the Samples selection according to the inclusion criteria include: Patients aged 18-above, Being able to communicate with researcher, The questionnaire was includes three parts, related to Socio- Demographic and clinical data, eight item-Morisky Medication Adherence Scale (8-MMAS), and Brief illness perception questionnaire (Brief-IPQ). Data was analysis by using SPSS version 25, descriptive statistics (percentage, frequency, SD, mean) used to describe socio-demographic data, Inferential statistics (chi- square test).  Conclusion: The study found that 34. 2% are from the age group (50-59), Were male, with a percentage of 54. 7%. and results revealed a total score of (Brief-IPQ) were (Moderate) with mean 43. 0684 and the eight item-MMAS total score were (low adherences) with mean 3. 7588. There is a positive correlation between the (Brief-IPQ) and the eight item-MMAS.