Aims: Studies on soil mechanics have established that when vibration is applied to an aggregate, it results in more efficient alignment of particles and reduces the energy required to impact the aggregate. Our aim was to develop a method of applying vibration to the bone impaction process and assess its impact on the mechanical properties of the impacted graft. Methods: Phase 1. Eighty bovine femoral heads were milled using the Noviomagus bone mill. The graft was then washed using a pulsed lavage normal saline system over a sieve tower. A vibration impaction device was developed which housed two 15V DC motors with eccentric weights attached inside a metal cylinder. A weight was dropped onto this from a set height 72 times so as to replicate the bone impaction process. A range of frequencies of vibration were tested, as measured using an accelerometer housed in the vibration chamber. Each shear test was then repeated at four different normal loads so as to generate a family of stress-strain curves. The Mohr-Coulomb failure envelope from which the shear strength and interlocking values are derived was plotted for each test. Phase 2. Experiments were repeated with the addition of blood so as to replicate a saturated environment as is encountered during operative conditions. Results Phase 1. Graft impacted with the addition of vibration at all frequencies of vibration showed improved shear strength when compared to impaction without vibration. Vibration at sixty Hertz was displayed the largest effect and was found to be significant. 3 Phase 2. Graft impacted with the addition of vibration in a saturated aggregate displayed lower shear strengths for all normal compressive loads than that of impaction without vibration. Conclusions Civil engineering principles hold true for the impaction bone grafting procedure. In a dry aggregate the addition of vibration may be beneficial to the mechanical properties of the impacted graft. In our system the optimal frequency of vibration was 60 Hz. Under saturated conditions the addition of vibration is detrimental the shear strength of the aggregate. This may be explained by the process of liquefaction.