The present invention generally relates to devices and methods for collecting and stabilizing biological samples, and more particularly, for collecting and stabilizing blood or other bodily fluids from a user's fingertip, earlobe, heel or other locations. The present invention also relates to sample collection devices that simplify the process for mixing the biological samples with an additive or additives, provide for efficient storage and safe transport of the samples, and provide for easy access to the samples for subsequent processing.