Chemokines induce chemotaxis of hematopoietic progenitor cells (HPC), and suppress their proliferation. In this study we report that SLC/Exodus2/6Ckine/TCA4 (hereafter termed SLC) is a chemoattractant for human CD34⁺ HPC. SLC mainly induces preferential chemotaxis of macrophage progenitors. We examined the chemotactic activity of CXCR3 ligands on CD34⁺ HPC because it has been reported that SLC is a potential ligand of CXC chemokine receptor, CXCR3, in addition to a CC chemokine receptor, CCR7. It was found that the CXCR3 ligands, MIG and interferon‐γ inducible protein‐10 (IP‐10), unlike SLC, did not induce chemotaxis of CD34⁺ HPC. In this regard, CCR7 ligands (SLC and CKβ‐11), but not IP‐10 and MIG, induce actin polymerization in CD34⁺ cells. On the other hand, CCR7 ligands and CXCR3 ligands, but not the CXCR4 ligand SDF‐1, showed inhibitory activity for proliferation of myeloid progenitor cells. Our results suggest that SLC is a potential trafficking factor for HPC, and that chemokines that bind CCR7, CXCR4, and CXCR3 have differential biological activities on HPC in terms of suppression and chemotaxis. J. Leukoc. Biol. 66: 455–461; 1999.