The disclosure provides a cell freezing and storage bag assembly and a method for using the assembly in banking eukaryotic cells for later seed train expansion. The bag is constructed principally of fluorinated ethylene propylene (FEP) fabric, and is designed to be filled such that the cell suspension has a very thin cross-section. The bag design includes at least an inlet conduit and an outlet or inoculation conduit, which can be sterilely welded to the source of the eukaryotic cells. The use of at least two sterile-weldable conduits allows for "closed system" filling of the bags, which significantly reduces the risk of contamination relative to other cell-banking methods. The bag also include a sleeve, which can be thermo-welded to form an enclosure, which protects the inlet and outlet conduits against contamination and mechanical damage during freezing, storage and subsequent thawing. In the method, once each bag is filled, its corresponding inlet conduit is sealed, and both the inlet and outlet conduits are enclosed within the bag's sleeve. This closed system method obviates the need for sterile environments (e.g. laminar flow unit).L'invention concerne un ensemble de sacs de congélation et de conservation de cellules, ainsi qu'un procédé d'utilisation dudit ensemble dans la constitution de banques de cellules eucaryotes pour amplification ultérieure de chaînes d'ensemencement. Le sac (1) selon l'invention est constitué principalement de tissu d'éthylène-propylène fluoré (FEP). La structure du sac comprend au moins un conduit d'entrée (2) et un conduit de sortie ou d'inoculation (3), qui peuvent être soudés de façon stérile à la source des cellules, permettant ainsi d'obtenir un remplissage des sacs en "système fermé", ce qui réduit sensiblement le risque de contamination. Le sac comprend également un manchon (8) pouvant être thermoscellé ("S") pour former une enceinte qui protège les conduits d'entrée et de sortie contre la contamination et les dommages mécaniq
