In the former West Germany, in specific venereal diseases legislation passed in 1953, only syphilis, gonorrhoea, ulcus molle, and lymphogranuloma venereum were defined as venereal diseases and subject to mandatory notification. The proportion of unreported cases was as high as 75% for syphilis and up to 90% for gonorrhoea. Epidemiological data for the past 10 years exist only on selected populations from research studies and are summarized in this article. In the former East Germany reporting of sexually transmitted infections (STIs) was mandatory and, due to the centralized organization, underreporting was considered to be low, although no specific studies have examined this. After the unification in 1990 of the two German states the West German laws were adopted in East Germany. Since 1982 - when the first AIDS case was reported in Germany - information on AIDS cases has voluntarily been collected at the national register at the AIDS Centre of the Robert Koch Institute in Berlin. The law governing the reporting of infectious diseases has recently been revised. Under the new Protection against Infection Act, which became effective on 1 January 2001, clinical diagnoses of STIs (with the exception of hepatitis B) are no longer notifiable diseases. Laboratory reporting of positive test results for Treponema pallidum has been introduced. With T. pallidum and HIV notifications, additional disaggregated data are collected. Since T. pallidum and HIV remain the only notifiable STIs, all other STIs have to be monitored through sentinel surveillance systems. These surveillance systems are currently being established. Under the new legislation, local health authorities have to provide adequate counselling and testing services for STIs, which may be provided free of charge if necessary.