Abstract. Almost all enterprises that use corrugated cardboard boxes for packaging their products face problems of transportation and storage. The main factor influencing the quality of cardboard during operation is the deformation and destruction of materials under the action of applied forces-these are the main phenomena that determine the mechanical behavior of materials. The paper analyzes the main properties that form the quality of corrugated cardboard. The fiber of technical cellulose is characterized by six properties. These are the average fiber length, the ability to compact in the wet state, the actual strength of the fiber, the cohesive ability, the coarseness of the fiber and the ability to grind. We also conducted a study on the effect of humidity on corrugated board samples. The strength properties of corrugated board samples were determined and the effect of humidity on them was studied. Attention is focused on the evaluation of the influence of fiber properties on the cardboard property. This property is defined as the" critical" fiber length. Recommendations are proposed to reduce the likelihood of corrugated cardboard consumer claims related to the collapse or subsidence of corrugated boxes during stacking.