abstract: The aim of the work was determination of kinetic durability of instant oat flakes. The research refers to shape changes, structure changes and crumbling susceptibility of instant oat flakes during testing in mechanical and pneumatic testers. The results of the research describe changes of geometric features of instant oat flakes under influence of external-dynamic forces during the testing process in two different types of testing devices. The estimation was based on analysis of granulometric composition before and after the testing processes. Analysis of results shows high kinetic durability of instant oat flakes.