The main goal of this study was to evaluate the possible influence of thymus extracts on the chemotaxis of PMN isolated from diabetic patients. The analyzed group consisted of fifty patients with insulin-dependent diabetes mellitus (IDD), and twenty healthy adults were taken as controls. The results showed, that PMN isolated from patients with IDD manifested the impaired chemotaxis toward zymosan-activated plasma (ZAP), plasma incubated with cellophane and supernate from E. coli culture. Both thymus extracts did not change the directed migration toward control plasma and toward ZAP. THYMEX-L did improve the migration of diabetic PMN toward plasma incubated with cellophane, whereas TFX-THYMOMODULIN ameliorated the impaired chemotaxis toward supernate from E. coli culture. Both thymus extracts can attract PMN obtained from healthy donors, but not the cells isolated from diabetic patients.