Polyurethane foams (PU), are found in various industrial and domestic applications due to their high energy absorption and sound absorption properties, especially in shock absorbers and noise control problems. This study investigates the effect of silica gel as additive filler in castor oil-based PU foam and its mechanical and acoustical properties are evaluated. Three different loading of 5%, 10%, and 15% silica gel is used as filler. For mechanical properties, the compression test is carried out. As the percentage of filler increases, the rigidity of the foam increases. The acoustical properties of the sample are tested using the two-microphone impedance tube method. Raw PU foams are seen to exhibit a reasonable sound absorption only in higher frequencies. The results show that the sound absorption coefficient of 10% filler PU foam has comparatively better sound absorption capabilities throughout all frequencies, ranging from 200 Hz to 4000 Hz, that it is exposed to. This can be attributed to the optimum number of voids present, compared to the highest number in 15% (high porosity) and lowest in 5%. The results show that the addition of silica gel up to a certain extent enhances both, the mechanical as well as acoustic properties. © 2019 Elsevier Ltd.