Abstract The segregation behavior of CoCu multilayers has been studied using 1–5 monolayers of cobalt and copper on a Cu(111) substrate. Substrate and overlayer-multilayer orders were confirmed using reflection high energy electron diffraction. Segregation and interdiffusion behavior were observed using Auger electron spectroscopy. The results indicate that well-ordered Co/Cu heterostructures can be grown epitaxially on Cu(111); the growth mode is predominantly layer by layer. Cobalt on Cu(111) exhibits an interdiffusion temperature of 250–275°C, while Cu/Co/Cu(111) bilayers and heterostructures exhibit an interdiffusion temperature of 500–550°C. The consequences of this segregation behavior for fabricating magnetic multilayers will be discussed.