Mycobacterium avium complex (MAC) is a common opportunistic infection in advanced human immunodeficiency virus (HIV), but splenic abscess formation is rare. We report a 35-year-old man with newly diagnosed HIV who presented with chronic cough, fever, abdominal discomfort, and pancytopenia. Imaging revealed a solitary splenic abscess. Cultures from sputum, stool, and abscess drainage in addition to lymph node and duodenal biopsies confirmed disseminated MAC. Additional diagnoses included cytomegalovirus viremia, esophageal candidiasis, and MAC-related granulomatous hepatitis. He was treated with rifabutin, ethambutol, and azithromycin) and started on antiretroviral therapy (ART) during admission. The patient was discharged on ongoing MAC therapy and ART. This case highlights a rare presentation of disseminated MAC as a solitary, drainable splenic abscess in severe immunosuppression, underscoring the need to consider atypical focal infections in advanced HIV.