Cytomegalovirus (CMV) gastritis is a rare opportunistic infection that often affects immunosuppressed patients. It is a DNA virus belonging to the Herpes family most commonly spread through contaminated bodily fluids such as blood, urine, saliva, tears, breast milk, semen, and vaginal fluids. Here, we present a case of a newly diagnosed HIV-positive patient with acquired immunodeficiency syndrome (AIDS) found to have a gastroesophageal (GE) junction ulceration with endoscopic characteristics suggestive of malignancy due to CMV gastritis in the absence of underlying malignancy. Most immunocompetent patients experience mild or no symptomatology and thus often require no treatment. On the contrary, immunosuppressed patients may be greatly affected by CMV including death. Because of this, it is necessary to treat and potentially prophylax against CMV within this population depending on the severity of immunocompromise and overall clinical suspicion. The most common treatments include ganciclovir, valganciclovir, cidofovir, and foscarnet. This case highlights the rare location and endoscopic appearance of CMV gastritis. Since the endoscopic appearance of CMV is highly variable, immunohistochemistry of biopsied mucosa is the only reliable method to correctly diagnose. In addition, this case illustrates the importance of maintaining a broad differential including rare and treatable diseases. Lastly, it summarizes the observed association of CMV ulcers at the GE junction with underlying malignancy reported in the literature.