A method and apparatus for filling one or more of a plurality of media plates each with a given quantity of media fluid. The media plates may be arranged in a self- supporting stack. The method comprises moving a carriage along a height of the stack of media plates to a position of a media plate to be filled and causing gripping means of said carriage to grip a lid of said media plate or, if said media plate has no lid, to grip a media plate directly above said media plate to be filled. The carriage is caused to rise to lift said lid, if present, and lift any media plates arranged above said media plate to be filled to provide access to an interior of said media plate. The interior, i.e. basin, of said media plate is filled with a given quantity of media fluid such as agar which may subsequently solidify to provide a growth medium for biological agents such as bacteria, yeast or the like. The carriage is caused to descend to replace said lid, if present, and return any lifted media plates to their former positions arranged above said media plate to be filled. The method does not require a media plate to be removed from the stack in order to fill it.