Abstract: We analyzed the morpho-functional state (geometric parameters, parameters of the surface protrusions, the membrane elastic modulus) of chicken blood neutrophils under photojetlag by using the method of atomic force microscopy. We found that chronic stress leads to the reduction of the surface area of the neutrophils membrane and its rigidity as well as increases the width of surface protrusions with decreasing its height. These changes may indicate the decrease of the secretory activity of neutrophils and activation of their motor ability.