Data were collected in Amsterdam in 1997 from the aids surveillance, from the HIV surveillance among pregnant women and visitors of a clinic for sexually transmitted diseases (STD), and from two 'alternative' HIV test sites, using various survey systems. The findings were compared with those of previous years. Aids was diagnosed in 1997 in 123 patients, in 194 in 1996. Of the 354 patients in whom aids was diagnosed in 1993-1997 in a hospital recording additional information, 113 patients (32%) only learned that they had an HIV infection when aids was diagnosed in them. In 1997, out of 225 pregnant women with an increased risk of HIV infection, 10 were HIV seropositive (4.4%); in 1996, this proportion was 3/285 (1.1%). Among those attending STD clinics, HIV infection was observed approximately as frequently as in earlier years: about 1% of heterosexual men and women.