In this study, a laboratory dryer was used for thin layer apple drying process and moisture ratio at any, drying time were compared by Newton, Page, Modified Page, Henderson and Pabis. logarithmic, two-term. two-term exponential. Wang and Singh. Thompson, diffusion approximation, Modified Henderson and Pabis, Verma et al. and Midilli et al. models. The effect of drying air temperature and velocity on the coefficients of the best suited moisture ratio model were determined by multiple regression method. Root mean square error (RMSE) and chi-square (chi(2)) were used for the determination of the best suitable model. In addition to these statistical parameter, the modeling efficiency (EF) was also determined. According to the results, Midilli et al. model is superior to the others for explaining drying behavionr of apple. It is possible to predict moisture content of the product with generalised model showing the effect of drying air temperature and velocity on the model constants and coefficients. (c) 2005 Elsevier Ltd. All rights reserved.