We report the case histories of 7 human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) who had a diagnosis of Castleman disease. All 6 patients who were treated responded to chemotherapy; immune reconstitution was observed in 5 patients, but it did not prevent relapse of Castleman disease. However, the mean duration of survival observed in this series (48 months) was most probably due to immune reconstitution resulting from receipt of HAART, which reduced the mortality associated with HIV disease.