Comorbidity of diabetes mellitus and hypertension is common, with both diseases and their treatment being able to cause liver function abnormalities, which can lead to liver failure. This study aims to access the effect of drugs used in the management of these diseases on liver function. A crosssectional study will be conducted, followed by a case-control design. Ethical clearance will be obtained from the Faculty of Health Sciences Institutional Review Board and administrative authorization from the various hospital directorates. The sampling procedure adopted will be consecutive and shall include all consenting patients aged 21 years and above, treated for hypertension, diabetes mellitus, or both. Pregnant women, patients with liver disease, viral hepatitis, as well as those on known hepatotoxic drugs will be excluded. Clinical, lifestyle, anthropometric data as well as venous blood samples will be collected and analyzed for liver enzymes (aspartate transaminase, alanine transaminase, and gamma glutamyl transferase) total or conjugated bilirubin, hepatitis B surface antigen and hepatitis C virus antibodies. Student T-test will be used to compare means and chi-square to test for proportion. Associated factors will also be determined using odds ratios. A p-value of <0.05 will be considered significant. The prevalence of liver function abnormalities shall be determined. Determinants of liver function abnormalities shall also be identified.