SDF-1β (stromal cell derived factor 1) also known as CXCL12 belongs to the CXCL chemokine family. Six isoforms of SDF-1 have been described: SDF-1α, SDF-1β, SDF-1γ, SDF-1δ, SDF-1ε, and SDF-1φ. SDF-1 is expressed by many organs, and it is most abundantly expressed in the pancreas, spleen, ovary, and small intestine. SDF-1 and its receptor CXCR4 are involved in the regulation of migration, survival, and development of multiple cell types, including human hematopoietic CD34 /CD38-/low and stromal STRO-1 stem cells. Stress-induced modulations in SDF-1 and CXCR4 levels leads to the recruitment of immature and maturing leukocytes from the BM reservoir to damaged organs as part of a host defense and repair mechanism. The SDF-1/CXCR4 system is involved in the establishment of organ metastasis in different cancers, for example in lymph node metastasis, in breast cancer and oral squamous cell carcinoma (SCC), and peritoneal metastasis in ovarian cancer. SDF-1 also binds to CXCR7, but it does not trigger typical chemokine signal transduction. CXCR7 is a scavenger receptor and regulates the extracellular accessibility of SDF-1. CXCR7 forms a dimer with CXCR4 and regulates SDF-1-mediated G protein signaling. CXCR4 and CXCR7 are involved in development as well as in cancer.