The strong release of heavy metals into the environment by several industries has meant that their recovery from wastewater has become a major topic of research in wastewater treatment. According to the World Health Organization, the most toxic metals are aluminum, chromium, iron, cobalt, nickel, copper, zinc, cadmium, mercury, and lead. The presence of cadmium ions in many industrial aqueous waste solutions is a complex example of pollution because of its high toxicity, which affects aquatic life and, in extreme cases, human life [1,2]. Among the technical alternatives for removing cadmium from aqueous solutions, liquid membrane systems have become an alternative separation technique for metals from wastewater solutions. They separation processes offer advantages over conventional solvent extraction such as the use of minimal amounts of solvent and low capital cost [3]. In this process the selection of a suitable carrier plays a crucial role in order to selectively extract a desired substance at the feed/membrane interface and to release it on the second interface (i.e. membrane/stripping phase interface) [4]. In the present work was studied a liquid membrane system containing trioctylmethylammonium chloride (Aliquat 336) as a carrier for the separation of cadmium cations from aqueous solutions. The influence of Aliquat 336 concentration in the organic phase, the influence of HNO3 concentration in the receiving phase and the transport time were studied. The process takes place with an efficiency of over 78%, when the concentration of Aliquat 336 in the organic phase was 0,2 mol/L, the concentration of HNO3 in the receiving phase was 1 mol/L and the transport time is 20 hours.