The hydrogen storage properties of metal-phosphate molecular sieves AlPO4-5, AlPO4-53, SAPO-34, (NH4)ZnPO4-HEX, and ZrPO-Py have been investigated at 77 K and 195, K and at pressures of 0-1.7 MPa. The hydrogen storage capacity is up to 1.0 wt % on AlPO4-5, 1.30 wt % on AlPO4-53, 1.42 wt % on SAPO-34, 0.68 wt % on (NH4)ZnPO4-HEX, and 0.72 wt % on ZrPO-Py at 77 K and 1.7 MPa. At 195 K and 1.7 MPa. the hydrogen storage capacity is 050 wt % on AlPO4-5, 0.48 wt % on AlPO4-53, 0.55 wt % on SAPO-34, 0.50 wt % on (NH4)ZnPO4-HEX, and 0.54 wt % on ZrPO-Py. The hydrogen storage capacities of samples increase with decreasing temperature. (C) 2008 American Institute of Chemical Engineers AIChE J, 54: 3017-3025, 2008