Injection moulded polypropylene samples containing low concentrations of talc, mica or wollastonite filler were fatigue tested in the flexural mode, at constant strain amplitude and 10 Hz frequency, and the induced stress, dissipation modulus, dissipated energy per cycle and surface temperature were recorded. Scanning electron microscope observations were made on fractured surfaces. Fatigue is characterized by self-heating until an equilibrium temperature close to 120°C for the highest strain amplitude. The onset of cracking can be easily detected by an abrupt decrease of the stress or dissipated energy. The cracks propagate over a few hundred micrometres from their initiation site (in the subcutaneous region), and then stop when 20 to 50% of the whole volume is damaged. The samples remain in this state for more than 95% of their lifetime and then undergo sudden rupture. The mineral fillers increase the energy dissipation (in the undamaged state) and accelerate sample failure. This latter involves two distinct kinetic regimes. Local (stress concentration effects, particle/matrix debonding) as well as macroscopic effects (narrowing effect of fillers on the processing-induced sample skin) can explain the disfavourable role of mineral fillers in fatigue.