Abstract: A vault for secure underground storage of valuables, comprising a one-piece molded container of a non-magnetic material and a removable lid for the container which, when in place on the container, prevents entry of moisture thereinto. An integral flange projecting outwardly from the container around its periphery is adapted to be embedded in the surrounding earth when the container is buried to thereby prevent the vault from being lifted due to its natural buoyancy should the water table in the earth rise above the bottom of the vault. Movable partitions are provided within the container for accommodating papers and other valuables of differing sizes and configurations.