The effect of HIV-1 on other infectious diseases in Africa is an increasing public health concern. In this review, we describe the role that three major infectious diseases--malaria, sexually transmitted diseases (STDs), and tuberculosis--have had in the HIV-1 epidemic. The high prevalence of untreated STD infections has been a major factor facilitating the spread of HIV-1 in Africa; with the synergistic interaction between HIV-1 transmission and genital herpes being of special concern for control of both diseases. Increased susceptibility to tuberculosis after infection with HIV-1 has led to a rising incidence and threat of increased transmission of tuberculosis. Clinical malaria occurs with an increased frequency and severity in HIV-1-infected individuals, especially during pregnancy. As with tuberculosis, STDs, and other communicable HIV-1-associated diseases, the net effect of HIV-1 might include increased rates of malaria transmission across communities. In addition to enhancing access to HIV-1 prevention and care, public health surveillance and control programmes should be greatly intensified to cope with the new realities of infectious disease control in Africa.