Migrant black African communities bear the brunt of the heterosexual HIV/AIDS epidemic in the UK. This study confirms the close links that exist between UK resident black Africans and their countries of origin. A total of 43% of men and 46% of women visited their home countries within the past 5 years. While there, men were more likely than women to have acquired a new sexual partner. Previous diagnosis with a sexually transmitted disease, and the use of condoms at last intercourse were independently associated with this practice. This represents a potential risk of HIV transmission, and highlights an area for targeted health promotion within these communities. By the end of March 2000 in the United Kingdom, diagnoses of HIV infections acquired in Africa formed 64% of all reported heterosexually acquired infections and 84% of those acquired abroad. Although the majority of individuals are thought to have acquired their infection before migrating to the UK, a growing number may have become infected since migrating to the UK. Relatively little is known about the contribution of travel and sexual mixing to HIV incidence among Britain's black African communities. However, as these communities become increasingly settled, it is likely that travel to and contact with their countries of origin will increase. We therefore wanted to determine the extent to which black African communities in London visited their home countries, and the factors associated with the acquisition of new sexual partners while abroad.