We review our efforts on atomic layer deposition (ALD) processes of Co and Ni thin films and their applications for nanoscale contact. First, PE-ALD Co processes was developed using various metal organic precursors and NH 3 plasma as a reactant. At optimal conditions, highly pure Co films were deposited with low resistivity down to 10 cm. For this case, epitaxial CoSi2 was formed through nitride mediated epitaxy, due the formation of a-SiNx interlayer. The effects of nitrogen during PE-ALD Co were also studied by using N2/H2 plasma. To improve the conformality, thermal ALD (T-ALD) using various metal organic precursors including Co(iPr-AMD)2 were investigated. Similarly, PE-ALD using NH3 plasma and thermal ALD based on metal organic precursors were developed. Highly conformal Ni film was deposited and the formation of Ni silicide was studied by post-deposition annealing. The film properties were studied using various analysis techniques. Thus, ALD of transition metal is expected to be a viable process for the formation of nanoscale contact in near future device fabrication.