A cryogenic canister assembly for biological specimens. The canister assembly includes a box having a lid and a base. The base has a bottom wall and sidewalls extending outwardly from the bottom wall around its outer periphery. Similarly, the lid includes a top wall and a sidewall extending outwardly from the top wall around the outer periphery of the top wall. Furthermore, the lid is dimensioned so that, when placed on the base, the lid sidewall overlies the base sidewall and forms a box having an interior chamber adapted to receive a plastic bag containing a biological specimen. A pair of U-shaped clips are insertable over opposed sides of the box to releasably lock the lid and base together. Both the lid and the base are constructed of cardboard.