The local strain rate sensitivity of polypropylene syntactic foams with polymer microballoons in the relative density from 0.5 to 0.8 is studied at the nominal strain rate ranged from 10-1 to 102 s -1. Johnson-Cook law is employed to show the viscoelastic properties of polymer syntactic foams. A microscopic investigation reveals that the strain rate sensitivity and the effect of localised deformations can be observed at the higher strain rate (50-100 s-1). The local deformation mechanism is different in different strain rate regimes due to the effect of local strain rate. At strain rates below 10 s-1, cell-face stretching is the dominant deformation mechanism. At strain rates from 50 s-1 to 100 s-1, cell-face stretching and cell-edge bending are the main deformation mechanism.