PURPOSE We retrospectively analyzed all patients with AIDS-related Kaposi's sarcoma (AIDS-KS) seen at one large California medical center to delineate factors that may have contributed to a relative decline in survival. METHODS Potential prognostic factors were analyzed individually, using the Cox proportional hazards regression model, for their association with survival. After a stepwise Cox regression procedure was applied to those factors that showed a significant effect on survival, a subset of factors that best predicted survival was identified. We then quantified the effect of the year of diagnosis on survival using a univariate Cox model. Next, we combined the year of diagnosis with the subset of prognostic factors previously identified into the Cox model to examine survival after adjustment for the prognostic factors. Survival distribution was estimated by the Kaplan-Meier method, and the 95% confidence interval for the median survival was computed using the modified reflected method. RESULTS In 688 patients, we identified four baseline variables that best predicted survival: CD4 cell number, hematocrit, number of KS lesions, and body mass index (BMI). Adjusted for these predictive factors, there was a significant improvement in survival for patients with AIDS-KS over the last 6 years. CONCLUSION Contrary to prior reports, survival has increased for patients with AIDS-KS. The apparent increase in observed mortality is most likely due to a decline in the CD4 cell number at presentation.