Author: Andrew Mathas School of Mathematics and Statistics F07 +61 2 9351-6058 (Ph.) University of Sydney +61 2 9351-4534 (Fax) Sydney, NSW 2006 Australia http://www.maths.usyd.edu.au/u/mathas/ Title: Matrix units and generic degrees for the Ariki--Koike algebras. Status: Submitted. Abtract: We compute the generic degrees of the Ariki--Koike algebras by first constructing a basis of matrix units in the semisimple case. As a consequence, we also obtain an explicit isomorphism from any semisimple Ariki--Koike algebra to the group algebra of the corresponding complex reflection group.