In this study, the effect of temperature on the rheological characteristics of apricot and date molasses was studied separately. Rheological characteristics of both molasses were evaluated in the shear rate range of 0.1-100 s(-1) different temperatures (10-40 degrees C). Power law model was used for the calculation of flow behavior index and consistency coefficients of molasses. Consistency coefficients of apricot and date molasses were in the range of 5.408-39.905 Pa s(n) and 0.910-2.852 Pa s(n), respectively. Molasses samples showed a non-Newtonian flow behavior. The effect of temperature on apparent viscosity was described by Arrhenius equation and calculated activation energy at the shear rate of 54.2 s(-1) was 41.42 and 38.19 kJ/mol for apricot and date molasses, respectively. An efficient predictive model for apparent viscosity values of molasses was constructed using Adaptive Neuro - Fuzzy Inference System (ANFIS) and this model showed satisfactory prediction with high coefficient of determination (0.979-0.999) and low root mean squared error (0.12-0.46). (C) 2011 Elsevier Ltd. All rights reserved.