A medical introducer apparatus for use in inserting an interventional device into a body vessel of a patient. The apparatus includes a housing having a proximal opening, a distal opening, and a chamber positioned between the proximal and distal openings. A sheath, defining a conduit for the interventional device, extends distally from the housing distal opening. A hemostatic valve system is provided in the housing chamber. The valve system includes a plurality of generally elastomeric valve members axially arranged in the chamber. The valve members each have a generally circular hole extending therethrough, which hole is sized for substantially leak-free passage of the interventional device. The valve members are aligned in the chamber to be sequentially penetrable by the interventional device, such that the hole in one valve member is covered by an adjoining valve member.