Syphilis and human immunodeficiency virus (HIV) infections are both transmitted sexually. Co-infection of HIV and syphilis alters the course of both diseases. Clinical presentation of syphilis in patients of HIV may be atypical. HIV-infected individuals are at risk of developing lues maligna, which is characterized by nodulo-ulcerative lesions associated with severe constitutional symptoms. Erythroderma secondary to generalized papulo-squamous lesions of secondary syphilis is also uncommon. Here we report two cases of atypical presentations of secondary syphilis in HIV-positive patients.