Aurora kinases play an important role in the cell cycle. These enzymes help establish mitotic spindles by directing centrosome duplication and separation and by regulating the spindle assembly checkpoint thereby helping control cytokinesis. An over-expression of aurora kinases has been reported in a variety of human tumors. In this study, we identified the expression of aurora-A and aurora-B kinases in canine malignant lymphoid cells. We also evaluated the effects of the aurora kinase inhibitor (ZM447439), and found that this inhibitor decreases cell viability, increases DNA content change, and leads to apoptosis in canine B- and T-cell lymphoid cell lines. The lymphotoxicity induced by ZM447439 in these canine lymphoid cell lines suggests that further in vivo evaluation of aurora kinase inhibitors as a potential treatment for canine malignant lymphoid tumors is warranted.