A liquid emulsion membrane (LEM) process is considered for the separation of nickel ions from dilute aqueous solutions. The liquid membrane is made up of D2EHPA as a carrier, organic diluent and emulsifying agent. The role of pH is very important in LEM process for extraction of nickel. The important variables affecting the LEM permeation process, including the membrane viscosity (surfactant concentration), volume ratios of emulsion to aqueous feed phase, carrier concentration, nickel concentration in the feed phase and internal strip acid concentration were systematically investigated. It is shown that liquid emulsion membrane system has a potential not only to separate nickel, but also to concentrate it with great efficiency.