Micro-modeling techniques for the simulation of masonry are a valuable tool, when combined with nonlinear constitutive laws, for the investigation of the behavior of structural masonry. Through the simulation of the behavior of the materials locally up to and beyond failure, it is possible to evaluate the global behavior of the structure under a variety of loads. While the strength of the masonry joints and the unit-mortar interface in tension and shear can be fairly easily described in terms of frictional and tensile strength parameters, the compressive strength of the joints, and by extension the masonry composite, are more difficult to estimate a priori. For this reason, in the present paper a detailed micro-modeling approach in which units, mortar and their interface are modeled as separate parts, is proposed for the estimation of the compressive strength and the Young’s modulus of the masonry composite. The approach proposed is based on well-known material and geometrical models. In addition, an analytical model for the estimation of the strength and the Young’s modulus of masonry is also presented. A number of experimental case studies of masonry in compression reproduced using micro-modeling techniques are presented. The group of simulated cases consists of solid clay bricks and lime/cement mortar arranged in stack and running bond. A satisfactory comparison is obtained between the experimental values and the predictions of the FE and numerical micro-modeling methods proposed.