A generic structural model to predict the effective thermal conductivity of fruits and vegetables during drying is proposed. The model was applied successfully in the case of apple, It combines a generic structural model for shrinkage and the distribution factor concept for thermal conductivity. The shrinkage coefficient and the distribution factor were used to develop the proposed physical model. Apparent density and thermal conductivity of the material can be calculated as a function of material moisture content and temperature using a minimum number of material characteristics. (C) 2002 Elsevier Science Ltd. All rights reserved.