The Expanded Fluid viscosity model was extended to visbroken heavy oils characterized into the following fractions: distillates and the residue SARA fractions (saturates, aromatics, resins and asphaltenes). To do so, a Western Canadian bitumen was visbroken at five different reaction conditions (temperature and residence time). Densities and viscosities were measured for each fraction and used to develop new property correlations based on conversion. The correlated fraction properties were then recombined to obtain the whole oil viscosity. The model matched the density and viscosity of all the visbroken oils in this dataset with average absolute deviations of 1.1 kg/m³ and 8%, respectively. The model successfully predicted the properties of a visbroken product from a chemically similar bitumen feedstock but not for those from a chemically dissimilar oil. This method is suitable for implementation in process simulators but is only recommended for whole oil feeds chemically similar to Western Canadian bitumen.