Interaction of hydrogen with aluminum phosphide clusters has been investigated using the density functional method of Becke's three-parameter hybrid functional with the nonlocal correlation of Lee, Yang and Parr. Berny structural optimization and frequency analyses are performed with the basis of 6-311 + G(d). Our results show large binding energies of a single hydrogen atom on small AlP clusters and large highest occupied and lowest unoccupied molecular-orbital gaps for (AlP)H and (AlP)5H making these species behave like magic clusters. Calculations on two hydrogen atoms on AlP clusters show large binding energies for (AlP)nH2 with n = 1, 3, 5 and 7. In general the binding energy of H and 2H are both found to decrease with an increase in the cluster size. And the calculations also suggest that hydrogen should be dissociated on (AlP)2 and (AlP)3. {\textcopyright} 2009 Elsevier B.V. All rights reserved.