Background Hypertension is one of the five causes of death globally, and it is a significant risk factor in more than 40% of deaths from cardiovascular and renal diseases [1]. The management of patients with hypertension requires the availability and affordability of medicines used to prevent and treat hypertension to achieve universal health coverage by 2030, as well as Rwanda's ministry of health strategic plan 2019–2024 of achieving 90% target of availability of essential medicines, including ones used for management of hypertension. Method In this study, a descriptive, cross-sectional study was undertaken in 14 public district hospitals, one central medical store, and its 30 branches across the country. Data was collected using excel sheets for surveyed antihypertensive medicines, and questionnaires were sent to all respondents. SPSS Version 22 and advanced excel were used to analyze the data. The treatment of affordability was evaluated by comparing if the patient's contribution to the total treatment was less than their daily salary wages. Results The overall availability of 15 selected antihypertensive medicines was 65%, 64%, and 71% for central medical stores, district stores, and district hospitals, respectively, compared to 80% targeted by WHO and 95% HSSP IV. Only 33.4% of individual items, the availability was greater than 83% and met the WHO target of 80%. The results have shown that stock levels were 40%, 28%, 83% and 20%, 21%, and 0% at maximum and minimum levels for RMS branches, district hospitals, and RMS for the central level, respectively. The results have shown that all surveyed antihypertensives was affordable. Conclusion The availability of antihypertensive medicines remains a challenge in Rwanda's health supply chain, though they are affordable. Therefore, more efforts and improvements are needed to increase the availability of antihypertensive medicines to provide quality health care to patients in need.