The configurations, electronic structures and magnetic properties of Fe(n)B (n = 1-12) clusters have been calculated within the framework of all-electron density functional theory. The calculated results indicate that the B atom prefers a surface site for all the lowest-energy structures of Fe(n)B with n = 1-9 and 11, while for Fe10B and Fe12B, the B atom is found to occupy a center site forming a B-centered Fe(n) cage. Furthermore, relatively large HOMO-LUMO gaps are found for Fe6B and Fe7B, indicating the chemical inertness of the two isomers. For Fe4B, and Fe12B, the spin magnetic moments of the Fe atom significantly increase, but the spin moments decrease slightly for all the other Fe(n)B clusters.