Introduction: Hypertension is a key precursor to cardiovascular and renal disease globally. According to WHO, Prevalence of hypertension was about 40 % globally in 2015 and 45% in Sub Saharan Africa in 2015. Despite much emphasis on treatment of the syndrome, the related blood pressure control remains poor or inadequate. Objective: The study sought to establish the patient related barriers to adequate blood pressure control among adult hypertensive patients in Kiambu Count Hospital in Kenya. Methods: A cross -sectional descriptive study method approach was used to examine sample of 330 patients selected through consecutive sampling technique in the medical outpatient chronic disease clinic. Multivariate logistic regression analysis was used to determine variables associated with inadequate or poorly controlled hypertension among adult patients. Results: Most of the patients were females (71.5%). However, the presence of inadequate blood pressure control was significantly higher among males (P-value= 0.009). Regularly taking of hypertension drugs for the last 6 months was significantly associated with adequate blood pressure control (p-value=0.033). The other barriers including single status, inadequate knowledge, employment and time duration since diagnosis of hypertension did not significantly affect blood pressure control status. Discussion: Males were 54% more likely to have inadequate blood pressure control compared to females (AOR=0.543; 95%CI=0.323-0.914). Patients with low adherence to treatment were 11% more likely to have inadequate blood pressure control than those with high adherence rate (AOR=1.093; 95%CI=0.224-5.332) though the association was not significant (p-value=0.912). Conclusion: Male gender was a major barrier to adequate blood pressure control. Patients who well adhered to treatment scheme for a duration of six months preceding the study had their blood pressure better controlled than those who did not. Male hypertensive patients need to be followed up to ensure they adhere to drug treatment in order to reduce the rates of inadequate blood pressure control and other related complications.