Multi-component prolate spheroid geometry was used in developing a non-dimensional isothermal liquid diffusion drying model for studying the moisture movement in the composite solids using a prolate spheroidal co-ordinate system. The developed models were solved using a finite difference method and were applied to simulate the drying process of multi-component parboiled brown rice and parboiled paddy. The observed drying characteristics of the input materials prepared by suitable hydrothermal treatment were obtained using a fluidised bed dryer at drying air temperatures ranging from 50 degrees C to 100 degrees C. In the multi-component parboiled brown rice drying model, the diffusion coefficients of bran were determined from the diffusion coefficients of the starchy endosperm, and for the parboiled paddy model the diffusion coefficients of husk were determined from the values of starchy endosperm and bran successively. By minimising the sum of squared differences (SSD) between experimentally observed and model predicted characteristics the liquid diffusion coefficients of bran and husk were determined at the various air temperatures studied. The developed models showed good agreement with the observed drying characteristics of the input materials. The temperature dependence of the diffusion coefficients of the parboiled paddy components was expressed by Arrhenius type of equations Bran: D-vb = 3.985948 x 10(-6) exp (-4096.003100/T-a), (r = 0.9923), Husk: D-vh = 1.655885 x 10(-5) exp (-4230.121506/T-a), (r = 0.9859). The diffusion coefficients of the parboiled paddy components were comparable to the recent findings on raw paddy and the differences encountered may be attributed to the properties of the component material.