Fibroblasts are mesenchymal cells which come from the embryonic mesoderm. Since tissue-specific mesenchymal cells are essential for normal organ development, the villous mesenchymal fibroblasts (VMF) are useful as a model system for studying the cellular mechanisms involved in regulating human placental growth. The VMF lie directly beneath the villous basement membrane; they synthesize HGF, CSF-1, gCSF and IL-6 and play an important role in the regulation of trophoblast growth and function. Studies show that paracrine interaction between placental VMF and the cytotrophoblast in anchoring sites is necessary for stimulating trophoblast infiltration. Human Villous Mesenchymal Fibroblasts are also useful tools to develop disease models for High Throughput and High Content Screening.