ObjectiveTo measure developments in survival patterns among United Kingdom adult AIDS cases.DesignA follow-up survey of cases reported voluntarily to the national surveillance schemes was undertaken to obtain up-to-date information on vital statusMethodsAll reporting clinicians who had a current AIDS patient not known to have died whose AIDS-defining illness was diagnosed before the end of September 1990 were contacted. A total of 3984 cases were included in the analysis.ResultsAn extra third of deaths other than those reported through routine channels were ascertained by follow-up. Median survival for patients diagnosed before and after the end of 1986 increased from 15 to 18 months for men who had sex with men presenting with Kaposi's sarcoma, from 10 to 19 months for other men who had sex with men and from 7 to 16 months for all others. Improvement in survival was greatest in the first 3 months. One-third of patients have been surviving 2 years or more. Factors observed with independent effects on improved survival are recent diagnosis, younger age and larger cumulative AIDS case load of reporting centre. HIV encephalopathy and other central nervous system symptoms may be associated with poorer survival.ConclusionsSurvival patterns have been changing and generally improving. Average survival for very recent cohorts tends to be underestimated because longer survival has been observed in patients for whom there is a longer delay between AIDS diagnosis and report to the Communicable Disease Surveillance Centre. Information on mortality is improved by active follow-up.