A high capacity microarrayer for spotting solution onto slides (4A1-4E10) in an automated microarray dispensing device. A microp late indexing device automatically moves, in sequence, a plurality of microplates (5) to a solution removal area. A dispense head(6) accesses each microplate at the solution removal area to remove solution from the microplate. The dispense head than moves to a slide positioning station to spot slides at the slide positioning station. In a preferred embodiment of the present invention, the microplate indexing station has at least one input stacking chamber for stacking microplates, and at least one output stacking chamber for stacking microplates. A beam walking beam indexer is for moving microplates from the input stacking chamber to the output stacking chamber.
