Abstract: A multicuvette rotor for use in a centrifugal analyzer defines a circumferential array of elongated radially extending cuvettes. The rotor includes a one-piece body member of material that is transparent at analytical wavelengths and has a planar upper surface and defines a circumferential array of elongated cuvette recesses, and a one-piece cover member of similarly transparent material that has a planar lower surface parallel to the planar upper surface of the body member. A continuous seal extends around each cuvette recess between the planar upper and lower surfaces to define the circumferential array of analytical cuvettes.