The geometries, stabilities, and electronic and magnetic properties of MAln (M = Cr, Mn, Fe, Co, Ni; n = 1-7, 12) clusters have been investigated systematically within the framework of the gradient-corrected density-functional theory. MAln clusters have similar geometries as that of Aln+1 clusters. For MAl12 clusters, only cobalt and the nickel atoms, whose atom radius are smaller, prefer a position at the cluster center of icosahedron. MAl3 clusters possess relatively higher stability. All the HOMO and LUMO states are non-degenerate and delocalized. The computed total magnetic moments of the lowest-energy structures oscillate with the cluster size, and NPA shows that the 3d electrons play a dominant role for the magnetism of the system. (C) 2009 Published by Elsevier B.V.