Abstract: A cell harvester tray formed from lightweight plastic for holding scintillation vials. In one embodiment the tray has a plurality of parallel, aligned wells, each well being adapted to support one scintillation vial. In an alternative embodiment the tray is provided with generally parallel aligned bores extending through a top surface and adapted to press-fit a scintillation vial whereby all of the top edges of the scintillation vials are maintained in a common level. Guide means are molded into the block for aligning the block in a cell harvester.