Flow through a turbine annular cascade is calculated using a three-dimensional Euler method based on unstructured tetrahedral meshes. The governing equations are integrated in time using an explicit RungeKutta time-stepping. Inviscid flux terms are diecretized using a cell-centered finite-volume formulation with the Roes flux-difference splitting. Tetrahedral meshes around turbine blade are generated using an advancing-front technique with a forced geometric periodicity between the blades. Good agreements are obtained between the present calculation and the experiment not only for the surface pressure distribution on the blade but also for the flow behavior through the flow passage between the blades.