The centrosome is a small organelle located near the nucleus which acts as the microtubule organizing center for the cell. Abnormalities in centrosome replication resulting in centrosome amplification have been identified in most of the common human cancers and implicated in the development of genetic instability and cancer. Research in centrosomes is evolving rapidly with identification of key regulatory proteins. This knowledge could help to explain the mechanisms of action of existing cancer treatments and also lead to the development of new molecularly-targeted therapy.