Abstract: The present invention relates to a grossing tool for preparing slices of tissue having a uniform predetermined thickness. The tool comprises a first and a second jaw for holding a tissue sample in a substantially fixed position therebetween. The first jaw and the second jaw have a first and a second array of prongs, respectively, for engaging the tissue sample. Furthermore, the prongs have parallel edges for guiding a cutting tool and form at least a cutting slot of a predetermined width corresponding to a predetermined thickness of a slice to be cut from the tissue sample. An actuator moves the first jaw and the second jaw in a plane of movement oriented perpendicular to the first and the second array of prongs between an open position and a holding position for holding the tissue sample. The grossing tool enables even an inexperienced user to cut tissue samples having a predetermined and substantially uniform thickness.