Abstract: An automatic slide stainer has a hollow enclosed framework including a base and a cover, the cover having a top annular platform. A dish is mounted upon said platform for containing a stain solution. A dish of increased width is mounted upon said platform adjacent said first dish and adapted to contain another stain solution. A reservoir tank having an outlet is mounted upon said framework and adapted to contain a rinse solution. A rinse tank is connected to said reservoir and projected up through said platform adjacent said stain dish and has an inlet. A pump is mounted upon said framework having an intake and an outlet. Conduits respectively interconnect the reservoir outlet and pump inlet, and the pump outlet and rinse tank inlet. A power-rotated upright hub is journalled upon said framework centrally of said platform and projects above said cover. A disc-shaped slide retainer plate is mounted upon and centrally secured to said hub for rotation therewith radially inward of said dishes and rinse tank.