Background <p>Hypertension is a major public health issue, particularly in low- and middle-income countries. Despite efforts to mitigate this problem, comprehensive studies on the magnitude of hypertension-related complications are lacking. This study aimed to assess the prevalence of hypertension-related complications and associated factors among hypertensive patients who were on follow up at Asella Referral and Teaching Hospital in Southeast Ethiopia.</p> Method <p>A hospital-based cross-sectional study was conducted at Asella Referral and Teaching Hospital from October 29, 2024, to December 21, 2024. Data were collected via structured questionnaires and patient chart reviews. Multivariate logistic regression was used to identify factors associated with complications.</p> Results <p>A total of 317 study participants were involved in this study. The mean age of the participants was 58.2 ± 11.5 years. In this study, the prevalence of hypertension-related complications was 47.3<b>%</b> (95% CI: 41.8, 52.7). The results of the multivariable logistic analysis revealed that a family history of hypertension (AOR 2.1, 95% CI: 1.3–3.5), a sedentary lifestyle (AOR 1.9, 95% CI: 1.16–3.12), and the discontinuation of antihypertensive medications (AOR 4.96, 95% CI: 1.87–13.12) were significantly associated with hypertension-related complications.</p> Conclusion <p>This study revealed a high burden of hypertension related complications, affecting nearly one out of every two patients. Key contributing factors included family history of hypertension, sedentary life style, and non-adherence to antihypertensive medications.</p> Clinical trial number <p>Not applicable.</p>