Pneumocystis jirovecii pneumonia (PcP) is a well-recognized major opportunistic infection in human immunodeficiency virus (HIV)-infected patients. During the 1980s, HIV pandemia turned PcP into a major worldwide medical and public health problem. With the introduction of Pneumocystis chemoprophylaxis and the development of highly active antiretroviral therapy for treatment of HIV infection, there has been a decrease in incidence of PcP in developed countries. However, the prevalence of AIDS-related PcP in developing countries remains high and poorly controlled because a lot of people do not have access to antiretroviral therapy or ignore that they are HIV infected. The author presents a review of the available data on PcP in developing countries and the expected evolution of the disease in these regions.This is a work within the Ibero-american Network on Pneumocystosis (Ibero-americanProgramme for Science, Technology and Development, CYTED).