A wide range of empirical correlations linking the Cone Penetration Test (CPT) end resistance qc and the resistance of shallow and deep foundations in sand have been published. Both National and European organisations are attempting to introduce standard methods into practice that unify these approaches. In this paper experimental data and finite element analyses are reviewed to examine the mechanisms governing foundation behaviour in a bid to move towards these unified approaches. For shallow foundations and non-displacement piles, sand creep was found to affect correlations between qc and the mobilised bearing resistance. For pile foundations direct correlations between qc and pile end resistance that were dependent only on pile installation method are reported. In the case of shaft resistance, constant correlation factors between qc and average shaft resistance are possible for non-displacement piles. For the case of displacement piles, correlations that include the effects of friction fatigue are recommended.