Background: Advanced HIV disease (AHD) represents a stage of HIV infection characterized by severe immunosuppression and a high risk of mortality. An understanding of the burden and associated risk factors for AHD is important in order to design programs targeted at prevention and treatment with the aim of reducing HIV associated morbidity and mortality. This study set out to determine the prevalence and risk factors for AHD in a tertiary health facility in Southern Nigeria as well as to ascertain the frequency of Same day initiation of Highly Active Antiviral Therapy in AHD patients. Methodology: This was a retrospective cross-sectional review of data from 419 adults and children diagnosed with AHD seen at the antiretroviral therapy clinic and Emergency department of the Rivers State University Teaching Hospital (RSUTH) over a 1year period. Details including personal bio-data and clinical information were obtained from the HIV registry of the hospital. Results: Four hundred and nineteen (419) patients were diagnosed with Advanced HIV disease between January 2021- January 2022 with a mean age of 35.8 years. Regarding the co-factors, Sixty- four (29.4%) of the 218 persons tested were positive for tuberculosis while 18(9.2%) of the 196 patients tested for cryptococcus infection were positive. One hundred and forty-eight (148) of the AHD population had CD4 cell count of Conclusion: Advanced HIV disease is highly prevalent despite the test and treat approach to care. Interventions aimed at prevention, adherence to therapy as well as early recognition and treatment is paramount in reducing the burden of AHD.