EDTA was used to complex nickel to allow a separation of trace amounts of nickel and cobalt in an emulsion liquid membrane (ELM), which contains P204, L-113A, liquid paraffin, kerosene and HCl. Separation time is about 20 min. Separated cobalt and nickel can be easily determined by spectrophotometer. The favorable range of pH is 4.4-5.2. The total separation coefficient is over 220 and the recoveries of cobalt and nickel are more than 95% and less than 8%, respectively. Among the coexisting ions investigated, only copper ion affects the separation.