Wax deposition modeling is complicated under oil/gas two-phase pipe flow and therefore remains poorly understood. One-dimensional empirical heat and mass transfer correlations are unreliably for deposition modeling in stratified flow, due to non-uniform deposit across the pipe circumference. A mathematical model has been developed to predict the deposit thickness and the wax fraction of deposit in oil/gas stratified pipe flow using a unidirectional flow analysis of non-isothermal hydrodynamics and heat/mass transfer. The predictions for wax deposition are found to compare satisfactorily with experimental data with three different oils for single phase and oil/gas stratified pipe flow. In particular, the reason that the deposit forming a crescent shape at the cross section of pipe observed in different experiments is revealed, based on the non-uniform circumferential distributions of two most important parameters for the wax deposition, diffusivity at oil-deposit interface, and the solubility gradient at the oil-deposit interface at different time. (c) 2016 American Institute of Chemical Engineers