In the present study, localized surface defects are modelled in inner race and outer race, and nonlinear dynamic behaviour of the system has been observed and quantified using Higuchi’s fractal dimensions. The Hertzian contact among the rollers and races, clearance and nonlinear damping are considered assources of nonlinearity. Dynamic responses show system behaviour as periodic, quasi-periodic and chaotic at different rotor speeds. The onset of chaotic motion is identified using Poincare´ maps and Higuchi’s fractal dimensions. The system shows low peak-to-peak amplitude of vibration responses at higher speeds in thepresence of defects. Results also indicate that Higuchi’s fractal dimensions can be effectively used as a diagnostic tool for health monitoring.