This study focused on biochemical aberrations in newly diagnosed and long standing hypertensives on anti-hypertensive therapy. One hundred and seventy two hypertensives were studied. Hydrochlorthiazide was the most used drug (41 percent). Of the hypertensive patients, 44 percent and 13.4 percent were hypokalaemic when 3.5 and 3.0 ml/l serum potassium respectively was used as criterion for defining hypokalaemia. In addition 13.8 percent had serum sodium levels ranging between 110- 120 mmol/l. Renal dysfunction was found in 0.05 percent of the patients studied as judged by both raised serum urea and creatinine. Lipids and lipoproteins abnormalities were also apparent in the patient groups, cholesterol and triglycerides being significantly raised (p less than 0.05 and p less than 0.001 respectively). High density lipoprotein cholesterol was significantly lower (p less than 0.001) in the patients whereas low density cholesterol was higher (p less than 0.001). In conclusion, this study highlights the need for constant biochemical evaluation on hypertensives on antihypertensive therapy as part of management of hypertensive patients.