Tensile strength and fracture toughness are two parameters used to define the ability of resisting fracture under tensile stresses. Adhesion of clays to metals is the strength of soil-metal interface. These properties of cohesive soils are fundamental and essential for geotechnical problems. Two types of compacted clays were used in this research — Calgary till and Regina clay. The fracture toughness KIc and tensile strength σt of two clays were measured by straight notched disk bending (SNDB) method and uniaxial direct tensile test, respectively. Results showed that the variations of σt with respect to moisture content and dry density were very similar with that of KIc. A strong positive correlation between these two properties was found. The tensile strength of compacted clays was curve fitted based on a double-porosity concept which considers the water among micropores and macropores in clay structure and their contribution to the strength of soils. The adhesion of compacted clays to stainless steel was measured using a modified direct shear box test. To obtain the adhesion factors, the adhesion was correlated with unconfined compressive strength of compacted clays. The effects of moisture content and pre-consolidation pressure on adhesion were investigated.