The survival function of the 100 first AIDS patients in Norway is presented and analyzed with respect to four factors obtained at the time of diagnosis; a) year of diagnosis b) initial AIDS related disease c) knowledge of HIV seropositivity prior to onset of AIDS and d) age at time of diagnosis. The median survival was 9.3 months. Among the known seropositive AIDS patients there were almost twice as many with Pneumocystis carinii pneumonia as initial AIDS related disease, as among the not known seropositives (relative risk 1.8). With Cox regression analysis we found that known seropositivity and age are factors that appear to influence survival, whereas year of diagnosis and initial AIDS related disease apparently do not. The mechanism whereby prior knowledge of HIV seropositivity leads to apparent increase in survival may be due to better follow-up and thereby an earlier date of diagnosis.