The present invention relates to a method for improving viability and/or stress tolerance of viable biological material and using the said material comprising applying hydrostatic pressure to said biological material; keeping the said viable biological material at the hydrostatic pressure for a predetermined time period; releasing the hydrostatic pressure; and using the said material for any desired purpose in accordance with any useful protocol. The usage of the said biological material incorporates any techniques, protocols that are applicable in the field of assisted reproductive techniques, biotechnical and/or biotechnological manipulations.