ABSTRACT— Human hepatic sinusoidal endothelial cells were derived from cadaveric human livers. Cells were grown in culture for several weeks to produce small patches of confluent endothelial cells. The ultrastructure of sinusoidal endothelial cells was examined, cell monolayers were stained immunocytochemically for von Willebrand factor antigen, and antigen in cell culture media was measured by enzyme-linked immunosorbent assay. Human hepatic sinusoidal endothelial cells contained von Willebrand factor antigen and Weibel-Palade bodies, were fenestrated, and released von Willebrand factor antigen into media in a time-dependent manner. Although in some respects human hepatic endothelial cells were different from vascular cells, there was no evidence that there were qualitative differences in their capacity to produce von Willebrand factor.