Herpes simplex esophagitis (HSE) occurs mostly in immunocompromised patients and rarely in immunocompetent patients. We encountered an elderly patient, a biologically immunocompromised patient with HSE who had characteristic endoscopic features and responded to acyclovir therapy. An 82-year-old woman presented with high-grade fever and epigastric discomfort for several days. A diagnosis of bacterial pneumonia was made based on imaging studies and cultures. Despite antibiotic treatment, epigastric discomfort persisted. Endoscopy revealed multiple exudative and circumscribed shallow ulcers with slightly raised edges in the mid-distal esophagus. Esophageal biopsy specimens showed multinucleated giant cells with Cowdry type A intranuclear inclusion bodies in epithelial cells, which were positive for herpes simplex virus-type 1 DNA by polymerase chain reaction. Because a diagnosis of HSE was made, she was treated with acyclovir, resulting in esophageal mucosal healing. In elderly patients with esophageal symptoms, HSE should be considered.