A newly-designed apparatus for extracorporeal perfusion achieving dual closed circulation has been described. Methods and techniques of operation of this investigative model have been outlined. The results of a series of experiments were presented to demonstrate adequacy of perfusion and maintenance of placental viability for up to 4–5 h. These tests of functional capability of the apparatus encompassed four major experimental approaches, i.e., fluid transfer rates from fetal to maternal circulation; dye perfusionstudies; oxygen studies; and glucose transfer and utilization, including the influence ofoxygen on glucose metabolism.