We investigated the thermal and plasma-enhanced atomic layer deposition (PE-ALD) of tantalum and titanium oxides from representative alkylamide precursors, Ta(NMe2)(5) (pentakis(dimethylamino)Ta, PDMAT) and Ti(NMe2)(4) [tetrakis(dimethylamido)Ti, TDMAT]. ALD of Ta2O5 by PDMAT with water or oxygen plasma produced pure Ta2O5 films with good self-saturation growth characteristics. However, incomplete self-saturation was observed for TiO2 ALD from TDMAT. The film properties including microstructure, chemical composition, and electrical properties are discussed focusing on the comparative studies between thermal and PE-ALD processes for both oxides. The results indicate that the PDMAT is a promising precursor for both thermal and PE-ALD of Ta2O5.