LiCo0.5Ni0.5O2 thin film cathodes were fabricated by electron beam evaporation and postannealing in oxygen atmosphere. As-deposit ed film showed almost amorphous characteristics, but included some crystalline phases. Hexagonal phase of LiCo0.5Ni0.5O2 was formed in the films annealed between 500 and 700 degrees C. The crystallinity of the film was improved as the annealing temperature increased to 700 degrees C. Open-circuit voltage (OCV) curves were measured. Especially the film annealed at 700 degrees C for 10 min showed a similar OCV curve to that of bulk powder cathode. It can be suggested that LiCo0.5Ni0.5O2 thin film is suitable for the cathode of Li rechargeable microbattery.