Abstract: A centrifuge adapter is formed in two sections divided by a plane that preferably extends through the longitudinal axis of the adapter. The two sections may be substantially identical in a first embodiment, each including a generally semicylindrical portion having a trough therein and further including an end portion. In a second embodiment, the adapter may comprise a first section including the entire bottom end portion for supporting the bottom of a centrifuge tube. The second section is formed generally as a semicylinder. When the first and second portions are assembled in facing relationship the troughs form a cavity for receiving a centrifuge tube therein. The sections of the adapter may be separate pieces, or they may hingedly connected along a pair of adajcent edges. The sections may be connected by projections extending from one section into corresponding cavities in the other section.