The field of tropical medicine has a long history due to the significance of the relevant diseases for the humanity. We estimated the contribution of different world regions to research published in the main journals of tropical medicine. Using the PubMed and the Institute for Scientific Information (ISI) "Web of Science" databases, we retrieved articles from 12 journals included in the "Tropical Medicine" category of the "Journal Citation Reports" database of ISI for the period 1995-2003. Data on the country of origin of the research were available for 11,860 articles in PubMed (98.1% of all articles from the tropical medicine category). The contribution of different world regions during the studied period, as estimated by the location of the affiliation of the first author, was: Western Europe 22.7%, Africa 20.9%, Latin America and the Caribbean 20.7%, Asia (excluding Japan) 19.8%, USA 10.6%, Oceania 2.1%, Japan 1.5%, Eastern Europe 1.3%, and Canada 0.6%. The contribution of regions, estimated by the location of the affiliation of at least one author of the published papers (retrieved from the ISI database), was similar: Western Europe 36.6%, Africa 27.7%, Latin America and the Caribbean 24.4%, and Asia 23.3%. The mean impact factor of articles published in tropical medicine journals was highest for the USA (1.65). Our analysis suggests that the developing areas of the world produce a considerable amount of research in tropical medicine; however, given the specific geographic distribution of tropical diseases they probably still need help by the developed nations to produce more research in this field.