The review summarizes the accumulated scientific results on the separation of mixtures of organic solvents by pervaporation and reverse osmosis. It has been shown that the pervaporation process makes it possible to achieve generally higher selectivity as compared to the reverse osmosis process; however, a number of developments, such as membranes from polyketone or PIM-1, make it possible to effectively separate components with similar molecular weights. Such membranes allow the main advantage of reverse osmosis-lower energy consumption due to the absence of phase transitions-to be gained. It is noted that with the use of reverse osmosis membranes, the highest efficiency can be achieved in the case of separation of mixtures of organic liquids that differ significantly in their polarity, a process that is especially important for the regeneration of polar extractants in the petrochemical industry.