The atomic structure of the (111) interface between CoSi2(typeAandB) and Si is investigated by high‐resolution transmission electron microscopy, combined with image simulations. TypeBinterfaces of CoSi2layers formed by thermal reaction of vapor deposited Co on (111) oriented Si, of Si/CoSi2/Si heterostructures, and of CoSi2precipitates formed by high‐dose Co implantation were examined. The coordination of the Co atoms at allB‐type interfaces is found to be eightfold, in accordance with theoretical predictions. TypeAinterfaces of CoSi2precipitates and continuous CoSi2layers, formed by ion implantation and subsequent annealing, showed clear evidence for the presence of sevenfold coordinated interfacial Co.