Interaction of a transition metal atom with defects in single-walled carbon nanotubes ( SWNTs) were investigated through density functional theory calculations. For three kinds of intrinsic defects ( single vacancies, double vacancies and Stone-Wales defects) in ( 5,5) armchair and ( 10,0) zigzag SWNTs, stable configurations were analyzed. The orientation of the specific bonds of the defects is related to the most stable configuration among several possible configurations. The stable adsorption sites and binding energies of a Ni atom on three intrinsic defects were calculated and compared to those on perfect side walls. All defects enhance Ni adsorption, and the single vacancy shows the most exothermic binding. These results shed light on the nature of the interaction of the transition metal with defects in SWNT, an important topic to the many aspects of carbon nanotubes interacting with transition metals. Particularly, this is useful for the fabrication of nanosized transition metal particles supported on carbon nanotubes.