Lues maligna is a severe and rare manifestation of syphilis, also known as malignant syphilis or ulceronodular syphilis and mostly occurring in patients with HIV infection. In this report, we present a case of lues maligna in an AIDS patient. Our report shows the typical clinical features of lues maligna and the important association between lues maligna and HIV/AIDS. Although the clinical manifestations of lues maligna are complicated and severe, the response to the therapy of penicillin is excellent.