Previous studies have revealed that the expression of CD38 on CD8⁺ T cells is a strong predictor of disease progression in human immunodeficiency virus (HIV)‐infected individuals. Those studies were performed using fresh patient samples over an extended trial period. After demonstrating the validity of assay results on cryopreserved cells, we performed a retrospective study using frozen cell samples to determine the predictive value of CD38 expression in patients with CD4 counts above 400 cells/μl. The CD38 expression as measured by antibody binding capacity and the CD38 median channel were shown to be associated with time to new opportunistic infection or death (both P < 0.001). These results suggest that CD38 expression on CD8⁺ T cells, whether fresh or frozen, provides a useful predictor of HIV disease progression. Cytometry 33:133–137, 1998. © 1998 Wiley‐Liss, Inc.