Mechanical-Biological Waste Treatment (MBT) is a combination of biological and mechanical processes carried out prior to waste disposal. Effective MBT systems utilize advanced technologies to optimize waste processing, enhance resource recovery, and protect the environment. The strength parameters of waste vary depending on its composition, the processing technologies employed, and the intended final disposal method. The primary objective of these processes is to reduce the volume of waste that requires disposal. To properly design a landfill, it is essential to understand the characteristics of MBT waste, such as shear strength, lateral stiffness, and compressibility. Shear strength is a particularly important parameter as it reflects the material's resistance to shear stresses along a slip surface within the waste mass. Cohesion and the angle of internal friction are key factors in describing the shear strength of waste, and these are determined through triaxial tests or direct shear tests. The triaxial test consists of three phases: saturation, consolidation, and shearing, which allow for a detailed examination of the mechanical properties of waste. This final paper will provide a detailed description of the procedure for determining the shear strength of waste using the triaxial test.