Background: The development of biopharmaceutics is the fastest growing segment of the present pharmaceutical industry. The analysis of proteins therapeutics is a challenging task due to their large size and complexity of spatial structure. Any changes in the primary, secondary, tertiary or quaternary protein structure can have huge impact on their function, efficiency and toxicity. Mass spectrometry proved itself to be a powerful tool for analysis of primary protein structure (amino acid sequence) and thanks to the development of new techniques in last years it is able to analyse higher order protein structures. One of these new techniques is hydrogen/deuterium exchange (HDX). HDX is based on exchange of amid protons with deuterium from solution on the protein backbone chain. Protons on the surface of protein are exchanging with deuterium much faster than protons buried inside of protein. HDX results could provide information about spatial protein structure and also about protein-protein interactions and protein-ligand interactions. Furthermore, by analysing of deuterium exchange in different time points this method could give information about dynamic changes of protein structure and dynamics of proteins interactions. Because of possibilities of this method, HDX become attractive method for characterization of protein biopharmaceuticals. Aims: This review article is focused on the utilization of mass spectrometry in biopharmaceutical industry and mainly on HDX method and its applications.