Introduction: Hypertension is a public health problem with a high prevalence in Nigeria. The cost of prescription medications is thought to be a barrier for many patients to access the healthcare they need. This study was aimed at identifying associated co-morbid conditions, the prescribing patterns and cost of prescription for the treatment of hypertension in an outpatient clinic at Lagos University Teaching Hospital. Materials and Methods: A cross sectional study was carried out. A total of 147 prescriptions were obtained from the case notes of patients treated at the LUTH outpatient department between February 2012 and August 2012. For each prescription, the number of drugs, the class and combinations of antihypertensives were recorded. The monthly cost of a 30-day anti-hypertensive supply based on the recommended daily dose was calculated. Results: The mean age of the patients was 54(+/-14) years and of the 147 prescriptions, 77(52.4%) was for females and 70(47.6%) was for males. The mean systolic blood pressure was 141.6 mmHg (+/-20.5SD) and mean diastolic blood pressure was 86.5 mmHg (+/-13.3SD). Of the 147 prescriptions, 112(76.2%) were for patients with co-morbidities. The frequency of prescription of the various classes of anti hypertensives are; diuretics 117(79.6%), angiotensin receptor blockers 78(53.1%), angiotensin converting enzyme inhibitors 65(44.2%), calcium channel blockers 65 (44.2%) beta blockers 54(36.7%) and centrally acting agents 12(8.2%). Average cost per month was =N=6611.47 (US$44). There was a statistically significant association between co morbid conditions and high cost of prescriptions with 73.7% of those with diabetes and 63.2% of those with renal disease having cost of prescriptions within the high cost group (p < 0.05). Conclusion: The cost per month is high and it is recommended that hypertension should be addressed as part of an integrated care program. Ingenious ways of health care financing also have to be promoted.