Acyl-CoA-binding domain-containing protein 6, also known as ACBD6, is a modular protein that carries an acyl-CoA binding domain at its N terminus and two ankyrin motifs at its C terminus. ACBD6 is not a ubiquitous protein, and its expression is restricted to tissues and progenitor cells with functions in blood and vessel development. ACBD6 was detected in bone marrow, spleen, placenta, cord blood, circulating CD34 progenitors, and embryonic-like stem cells derived from placenta. In placenta, the protein was only detected in CD34 progenitor cells present in blood and in CD31 endothelial cells surrounding the blood vessels. Human ACBD6 may represent a cellular marker for primitive progenitor cells with functions in hematopoiesis and vascular endothelium development.