Copper/single-walled carbon nanotube (SWCNT) composites were fabricated by electrodeposition using a freestanding SWCNT film as a template. The SWCNT films were directly electrodeposited to form copper/SWCNT composites. An acidic copper sulfate bath was employed as a basic plating bath, and the effects of additives to the basic bath on the morphologies of copper deposits were examined. Poly(ethylene glycol), chloride ions (Cl-), bis(3-sulfopropyl)disulfide (SPS), and Janus green B (JGB) were added individually or in combination as additives. Electrodeposition of copper occurred only on the surface of the SWCNT film when using the basic plating bath without additives. In contrast, copperwas deposited not only on the surface but also in the interior of the SWCNT film when using the plating baths containing at least PEG and Cl-, resulting in copper/SWCNT composites. Electrodeposition of copper inside the SWCNT film was accelerated dramatically when all four additives (PEG, Cl-, SPS, and JGB) were added to the basic bath. This novel fabrication method of copper/CNT composites using CNT films as templates can be applied to the fabrication of various types of metal/CNT composites. (c) The Author(s) 2017. Published by ECS. All rights reserved.