In an attempt to understand the influence of fillers on the rheology of composite melts, oscillatory shear experiments were carried out on Nylon-6 composites containing short glass fibres (length <1mm) of different weight fractions: 0% (PA6), 15% (PA6-15GF) and 30% (PA6-30GF). Oscillatory time sweep experiments carried out within the Linear Viscoelastic Region (LVR) using a parallel plate rheometer showed an increase in complex viscosity as a function of time for filled systems. PA6-30GF samples exhibited a greater increase in viscosity than PA6-15GF samples while unfilled PA6 samples showed a constant viscosity. While an increase in fibre orientation usually results in the reduction of complex viscosity, these results suggest that other phenomenon such as fibre migration and flow induced crystallisation aided by fillers could be occurring. Differential Scanning Calorimetry (DSC) was used to characterise the crystallisation behaviour of the samples. X-Ray Computed Tomography (X-CT) was employed to measure 3-dimensional fibre orientation and local fibre concentration in the fibre filled samples at a resolution of 2.5μm. The research work aims to gain a better understanding of how specific flow mechanisms impact rheological properties of high fibre content composites which are commonly used in industrial processes. Keywords: Crystallisation, Nylon, Glass fibres, Computed tomography