Voluntary testing for antibody to human immunodeficiency virus (HIV) was offered to 4929 antenatal patients attending two hospitals in South Manchester during a 12 month period in 1989/90 in order to assess the feasibility of obtaining seroprevalence data by this method. Of these patients, 1728 (35%) agreed to a named test, 1396 (28%) to an unlinked anonymous test and the remaining 37% declined to be tested. The proportion of women tested increased from 22% to 88% over the period, and was similar in those with and without an identified risk factor for infection. One HIV antibody positive patient was found; she was tested anonymously and had no identified risk. The substantial cost in time and money required to establish the universal voluntary testing programme and the incomplete patient compliance confirm the importance of the unlinked anonymous surveys currently being established in the UK to monitor seroprevalence in sentinel populations.