Abstract: A simple chemotaxis apparatus and method wherein surface tension, capillary action, and hydrophobic forces are used to hold cell suspensions, chemotactic factors, and control fluids in place on both membrane filters and chemotaxis plates. In one embodiment, chemotactic factors and controls are placed at preselected areas on the top surface of a bottom plate, while a membrane filter topped with cell suspensions is placed above the bottom plate so that the drops of chemotactic factors and controls contact the filter membrane directly below the locations of the cell suspensions. In another embodiment, the preselected locations on the bottom plate are rimmed wells that are filled with chemotactic factors and controls. Hydrophobic coating is used to limit fluid movement on the filter membrane and on the bottom plate. Occluding materials or monolayers of cells are used to further limit the gravitational fluid flow in the preferred embodiments.