Intrinsically disordered proteins (IDPs) are a specific and diverse group of proteins that, under physiological environmental conditions, do not possess higher levels of structural organization, but are found in a form resembling denatured proteins. When IDPs are exposed to conditions that are denaturing for ordered proteins, such as high and low temperatures or strongly acidic or basic pH of environment, they acquire transient forms of ordered structure. Also, a large number of typically ordered, globular proteins have intrinsically disordered regions (IDRs) in their structure. Contrary to the established view that the function of proteins depends on their ordered structure, research has shown that IDPs possess various molecular functions regardless of the absence of structure. Due to the lack of higher orders of structure, IDPs have the ability to recognize a large number of different biomolecules and interact with them, and during these interactions they partially fold and acquire a more ordered structure. Due to their flexibility and plasticity in intermolecular interactions, IDPs and proteins with intrinsically disordered regions are often involved in cell signaling processes, regulation of transcription and translation, and also function as molecular chaperones. Based on their diverse roles, as well as resistance to denaturation under unfavorable conditions, IDPs probably have a pronounced biological significance in adaptive processes of organisms to abiotic stress factors. In order to evaluate their potential importance in the process of adaptation to hypometabolic living conditions during phases of arrested development and developing cold resistance, in this dissertation 5th instar larvae of th European corn borer Ostrinia nubilalis were used. In order to survive the cold winter months this species enters a specific resting state called diapause. During diapause, corn borer larvae undergo biochemical and molecular changes that allow them to survive only on stored energy sources and to develop resistance to extremely low winter temperatures. For this reason, the European corn borer is often used as an in vivo model system for studying these processes. In this dissertation, a method was established and optimized for enriching the content of IDPs, validation of the enrichment procedure with specific 2D polyacrylamide gel electrophoresis and isolation of disordered proteins from whole-body homogenates of larvae that were subjected to different temperature treatments to develop low temperature resistance. Isolated proteins were identified using liquid chromatography coupled with tandem mass spectrometry. Also, the degree of intrinsic disorder of the identified proteins was determined by in silico analyses, quantitative and qualitative parameters of their disorder were evaluated, and the functional characterization of the proteins was performed. The relative expression of selected genes for proteins with a significant degree of intrinsic disorder was also examined in 5th instar larvae that were reared under non-diapausing conditions, as well as diapause-inducing conditions that also lead to the development of cold resistance. The results showed that in this species there is a significant content of IDPs and proteins with disordered regions, and that the proportion of proteins with IDRs is correlated with the acquisition of cold resistance. The expression of most of the analyzed genes is also correlated with this adaptation. The results of this dissertation provide new insights into the molecular basis of processes that enable the European corn borer to adapt to unfavorable living conditions characterized by a reduced metabolic rate, limited energy sources for basal metabolism, as well as the negative effects of exposure to low temperatures on the functional and structural homeostasis of proteins and processes they are involved in.