A fully developed turbulent pipe flow of non-Newtonian fluids was investigated numerically using the large eddy simulation (LES) method. The present investigation mainly focuses on the rheological and hydrodynamic behaviour of the pseudoplastic (shear-thinning) and dilatant (shear-thickening) fluids over a wide range of flow behaviour indexes 0.75, 0.8, 1, 1.2, 1.4, and 1.6 at a simulation Reynolds number of 12,000. The computations are based on a finite difference scheme, secondorder accurate in space and time. The numeric resolution is 65 3 grid points in r, θ and z directions, respectively. According to the results, the shear rate profiles of the pseudoplastic decreased while the dilatant fluid improved with a higher flow index along the pipe radius. Additionally, the elevated flow index caused a rise in the fluid viscosity close to the wall, which raised the friction factor.