Porous polyurethane composites containing hollow silica microspheres were prepared by one-step bulk polymerization to study cyclic compressive and dynamic mechanical properties of the composites. Cyclic compression testing was conducted to record the stress versus strain curves during the loading and unloading cycles and in order to study the compressive behavior and time-dependent recovery of the composites. Effect of frequency on the dynamic mechanical properties of the composites was also evaluated using dynamic mechanical analysis. Master curves were constructed based on time-temperature superposition principle in order to show long-term dynamic mechanical behavior of the composites.