Crude oil is formed by several hydrocarbons. At the reservoir, due to high pressures and temperatures, it is found in the liquid form. As the oil flows, its pressure drops as well as its temperature, due to a heat loss to the ambient, causing liberation of the gas dissolved in the oil and it becomes a two-phase flow. Further, if the temperature drops below the initial crystallization temperature, crystals precipitation occurs, forming a solid phase deposit at the inner pipeline walls. Wax deposition is one of the most critical operational problems regarding oil flow through subsea pipelines. This work, wax deposition in a multiphase flow is numerically predicted. The influence of a water phase and pipe inclination angle in the deposition rate is investigated. The Drift Flux Model was employed to predict the multiphase flow and the wax deposition was determined based on a Molecular Diffusion Model. The methodology was validated by investigating the flow in a short pipe, reproducing laboratory experimental conditions. The wax deposit thickness presented a excellent agreement with the experimental data and against results of commercial code OLGA. An existing oil production well in Campos Basin was modeled, and the impact in pressure drop due to cross section area reduction caused by progressive wax deposition on the pipe wall. The results obtained in this study demonstrated good physical consistency and a reasonable agreement with the compared experimental database.