To explore the possibility of achieving a solid-state high-capacity storage of hydrogen for onboard applications, we have performed first-principles density functional theoretical calculations of hydrogen storage properties of beryllium oxide clusters (BeO)n (n = 2-8). The gravimetric density of H2 adsorbed on BeO clusters meets the ultimate 7.5 wt % limit, recommended for onboard practical applications. In conclusion, beryllium oxide clusters exhibit a remarkable solid-state hydrogen storage.