Gonorrhoea is a sexually transmissible disease (STD) characteristic of a core group of individuals and their contacts. From the experience of a Sydney STD clinic, as well as local and national population-based reports, trends in heterosexually acquired gonorrhoea in Australia over a decade were examined. An overall decline of 90% in case numbers between 1981 and 1989 was found, with an average yearly decline of 30%. The improved compliance with condom use by Sydney prostitutes and their clients could have been a major factor. This occurred in an environment of peer and public education about AIDS and the decriminalisation of prostitution. Improved health professional training and public access to specialist STD services against a background of demographic changes may also have contributed. However a persistent "seeding" of penicillinase-producing strains of gonorrhoea from Southeast Asia through men not using condoms was detected. These data have potential implications for the importation of heterosexually acquired human immunodeficiency virus infection into Australia.