Abstract: A screen using RNAi methods was used to test the entire set of protein kinases in Drosophila for an effect on mitosis. Most kinases previously known to be involved in the cell cycle were identified, providing validation of the approach. A mitotic function was found for a number of kinases not previously known to be involved in the cell cycle. Materials and methods are therefore provided for control of the cell cycle using modulators of expression or activity of kinases not previously known to act in mitosis, including human orthologues thereof.