Lime treatment is an attractive technique for soil improvement in the construction of rail tracks and pavement layers, in slope protection of earth dams, and as a support layer for shallow foundations. However, there are no dosage methodologies based on rational criteria as in the case of soil-cement technology, where the voids/cement ratio is shown to be a key parameter for the estimation of both strength and stiffness. The present study, therefore, was aimed at quantifying the influence of the amount of lime, porosity, and voids/lime ratio on the initial shear modulus (G(0)) and unconfined compressive strength (q(u)) of a lime-treated clayey sandy soil. From the results of unconfined compression tests and bender elements measurements, it was shown, for the soil-lime mixtures investigated, that the voids/lime ratio is an appropriate parameter to assess both initial stiffness and unconfined compressive strength. Also, a unique G(0)/q(u) versus voids/lime ratio relationship was established linking the soil-lime mixture initial stiffness and compressive strength. DOI:10.1061/(ASCE)GT.1943-5606.0000470. (C) 2011 American Society of Civil Engineers.