Nickel multiwalled carbon nanotube (MWCNT) composite plating was studied using a sulfamate-based bath. The effects of additives, current density, and bath temperature on the microstructure of Ni-MWCNT composite films were examined. The content of MWCNTs and internal stress of the composite films were also investigated. The addition of both sodium saccharin dihydrate and 2-butyne-1,4-diol caused a decrease in the voids formed in the composite films. The amount of voids in the composite films increased with increasing bath temperature. A Ni-MWCNT composite film with 0.4 mass % MWCNTs, no significant voids, and low internal stress was fabricated by adjusting the bath composition and electrodeposition conditions. (c) 2007 The Electrochemical Society.