The relationships between microhardness and mineral content and microhardness and Young's modulus have been determined for cortical bone exhibiting a wide range of mineral volume fractions. These relationships have also been determined for a hydroxyapatite reinforced polyethylene composite which is considered to be an analogue material for bone. Strong nonlinear relationships were found between the variables for both materials. For a given volume fraction of mineral the hardness of the natural bone tissue was found to be considerably higher than that of the analogue material. This was attributed to the different ways in which the mineral phase is bound to the matrix in the two materials. The relationship between microhardness and Young's modulus was similar for both materials. The strength of the relationships found suggest that microhardness data is a viable means of estimating the Young's modulus of specimens that do not easily lend themselves to convential testing procedures.