Thin layer drying characteristics of parboiled wheat were studied for a temperature range of 40-60 degreesC, using semi-theoretical and empirical models. The total drying occurred in falling rate period, signifying the influence of moisture diffusion during drying. The effective diffusivity varied from 1.218 x 10(-10) to 2.861 x 10(-10) m(2)/s over the temperature range. Temperature dependence of the diffusivity was well documented by Arrhenius-type relationship. The activation energy of for moisture diffusion during drying was found to be 37.013 kJ/g mol K. The thin layer drying characteristics of parboiled wheat was well fitted with the Two-term model with the drying constants being in a linear relationship with drying temperatures. (C) 2004 Published by Elsevier Ltd.