A numerical study was carried out to investigate the effect of internal radiative heat transfer on the transition of flow modes in an axisymmetric Czochralski oxide melt. Results were obtained over a wide range of absorption coefficients of the melt and the crystal rotation rates for two different Marangoni numbers, 0 and 2.82 x 10(4). As a result, it was found that melt convection with only the steady flow mode exists in the optically thicker melt, while a transition from the steady flow mode to the axisymmetric oscillatory one occurs in the opaque and optically thinner melt as the crystal rotation rate increases. This flow transition is also affected by the Marangoni effect in the melt.