Wax deposition is one of the major risks that causes a serious threat to pipeline transportation during operation, if not prevented. The remediation actions are usually costly; hence mitigation methods are in place to completely avoid the issues from happening. The wax deposition modelling technique has been accepted as a tool to design and continuously optimize the wax management strategy. Non-Newtonian oil-wax viscosity is an important parameter affecting wax deposition in pipelines. The present and widely used viscosity model assumes exponential behavior as observed in the emulsion system. In this paper, it is demonstrated that this assumption may not be suitable for Malaysian waxy crude oil applications due to instantaneous change of viscosity below WAT and PPT. This paper focuses on the application of the Pedersen and Ronningsen viscosity model available in the commercial fluid and flow simulators namely PVTsim ®, Multiflash ® and OLGA ® which are widely used by the flow assurance fraternities, and how it will impact wax deposition prediction accuracy specifically when applied to Malaysian waxy crude oils. © 2023, IIUM Engineering Journal. All Rights Reserved.