In the present study, a numerical method is proposed for simulating the coupled three dimensional heat and mass transfer processes during convective drying of apple slices. Spectral collocation method (pseudospectral method) is applied for discretizing both the space and time variables based on the Jacobi Gauss Lobatto (JGL) interpolation points. Also operational matrices of differentiation are implemented for approximating the derivative of the spatial and temporal variables. The external flow and temperature fields were simulated through the Fluent CFD package. The convective heat transfer coefficient is calculated from the lumped system analysis and convective mass transfer coefficient is computed through the analogy between the thermal and concentration boundary layers. The model is validated against experimental data in a range of air temperatures from 60 degrees C up to 90 degrees C. The results illustrate a remarkable agreement between the numerical predictions and experimental results, which confirm robustness, computationally efficient and high accuracy of the proposed approach for predicting the simultaneous heat and mass transfer in apple slices. (C) 2017 Elsevier Ltd. All rights reserved.