This work is about the influence of filler type (talc, glass spheres, thermoplastic elastomer (TPO)) and filler content on the fatigue behaviour of filled polypropylene (PP). The tests were run at room temperature under stress controlled tension-tension conditions on injection moulded specimens. Among the materials with the strengthening particles no significant difference could be found in the Wöhler-diagrams. In isocyclic stress-strain diagrams (comparable to isochronous stress-strain diagrams that are used for creep characterisation) and also in the dependence of the dynamic secant modulus (characterizes creep and damage) and the pure dynamic modulus (characterizes damage only) significant differences could be found. Contrary to the types with the strengthening particles (brittle fracture), the pure PP and the PP filled with TPO showed ductile fracture in the investigated load range.