A storage unit for biological samples has a horizontal footprint and multiple storage compartments separated by intermediate walls and enclosed by a peripheral frame. The storage compartments have first and second openings and are tailored to the shape of a biopsy cassette or a glass slide and have a retention mechanism preventing the essentially vertical cassettes or slides in the storage compartments through the first opening and/or the second opening from falling out through the first opening and/or the second opening. A transfer system allows at least two storage units or at least one storage unit and one collection unit to be situated one above the other in register and displaced in relation to one another. The transfer system has a manipulator by which a biopsy cassette or a glass slide may be pushed from one storage unit to another, or into the collection unit.