Beryllium nuclei are expected to be mainly produced by the fragmentation of primary cosmic rays (CR) during their propagation. Therefore, their measurement is essential in the understanding of
cosmic ray propagation and sources. In particular, the 10Be/9Be ratio can be used as a radioactive clock providing the measurement of CR residence time in the Galaxy. In this contribution, the
measurement of the 7Be, 9Be, and 10Be fluxes and ratios based on data collected by AMS are presented.