Abstract: The improved virus titration and identification system of the present invention comprises a transparent plate having a plurality of spaced wells arranged in a plurality of spaced rows. A dried, preferably freeze-dried, amount of viable specific virus antiserum or a dried, preferably freeze-dried, amount of normal serum is disposed in each well. All wells containing a given specific antiserum are aligned in a single row of a given direction and all of the rows which contain antiserum are aligned with each other.In one embodiment, the system includes a reference locator disposed on the transparent plate and movable relative thereto. The locator comprises a sheet defining a pair of intersecting light-transmitting windows of specific length. Such windows may be slots in the sheet and may intersect each other at about their mid-points. Preferably, the plate has the wells arranged in a rectangular pattern, so that there are rows of wells in two different orientations at about 90.degree.