Elevated alanine aminotransferase (ALT) levels in Human Immunodeficiency Virus (HIV) infected people is a major concern in the world and especially in Africa. It may lead to liver failure and even death. Certain antiretroviral (ARV) drugs, such as nevirapine and efavirenz, are known to cause toxicity. Other causes of elevated ALT are viral hepatitis, the HIV virus itself and other drugs such as anti-tu-berculosis drugs and alcoholism. The study aimed at determining the prevalence of elevated ALT levels in HIV positive patients on antiretroviral therapy during the period 2013 to 2014. This was a retrospective study which included 267 patient records from Katutura and Windhoek Central hospitals in Windhoek, Namibia. The subjects' ages ranged from 21 to 82 years. The patients enrolled were on the first line treatment and their ALT levels were recorded at each monitoring period. ALT levels, viral hepatitis results and the antiretroviral therapy (ART) regimen were the most important aspects included in the study. Out of 267 patients, 18% had ALT elevation associated with grade 1 to 4 toxicity levels. The study found that 1.4% of patients developed severe liver toxicity (grade 3 and 4 toxicity). Toxicity occurred throughout the treatment period but was the highest at six months of treatment. Patients on nevirapine based regimens had lower toxicity compared to those receiving efavirenz based regimens. Patients who had HIV and viral hepatitis co-infection had high toxicity although the study found no severe hepatotoxicity in these patients.