Process for preparing isocyanates, which comprises the following steps: a) reaction of at least one amine with phosgene in the presence of a solvent, to give a liquid stream containing the corresponding isocyanate and possibly solvent and a gaseous stream containing hydrogen chloride, phosgene, solvent and also low boilers and inerts, b) fractionation of the gaseous stream containing hydrogen chloride, phosgene, solvent and also low boilers and inerts by partial condensation to give a liquid phase which consists essentially of solvent, phosgene and hydrogen chloride and is conveyed to the top of a stripping column and a gaseous stream consisting essentially of hydrogen chloride and phosgene and also solvent in concentrations of not more than 30% by weight, based on the weight of the gaseous stream, and also low boilers and inerts, c) fractionation of the liquid phase which is introduced into the stripping column in step b) and consists essentially of solvent, phosgene and hydrogen chloride to give a solvent phase which is taken off in liquid form from the bottom of the column and has a phosgene concentration of < 0.1% by weight, based on the weight of the liquid bottom stream, and a gas phase which is taken off at the top of the column and contains phosgene, hydrogen chloride, low boilers and inerts and also solvent in concentrations of < 30% by weight, based on the weight of the gas phase, d) recirculation of the solvent phase obtained in step c) to the phosgenation in step a), e) introduction of the gas phase obtained in step c) into an absorption in which the phosgene present in the gas phase is absorbed in the same solvent which is also used in the phosgenation in step a), giving a phosgene solution having a concentration of 20-80% by weight of phosgene, based on the weight of the phosgene solution, f) recirculation of the phosgene solution obtained to the phosgenation in step a). a) reaction of at least one amine with phosgene in the presence of a solvent, to give a liquid stream containing the corresponding isocyanate and possibly solvent and a gaseous stream containing hydrogen chloride, phosgene, solvent and also low boilers and inerts, b) fractionation of the gaseous stream containing hydrogen chloride, phosgene, solvent and also low boilers and inerts by partial condensation to give a liquid phase which consists essentially of solvent, phosgene and hydrogen chloride and is conveyed to the top of a stripping column and a gaseous stream consisting essentially of hydrogen chloride and phosgene and also solvent in concentrations of not more than 30% by weight, based on the weight of the gaseous stream, and also low boilers and inerts, c) fractionation of the liquid phase which is introduced into the stripping column in step b) and consists essentially of solvent, phosgene and hydrogen chloride to give a solvent phase which is taken off in liquid form from the bottom of the column and has a phosgene concentration of < 0.1% by weight, based on the weight of the liquid bottom stream, and a gas phase which is taken off at the top of the column and contains phosgene, hydrogen chloride, low boilers and inerts and also solvent in concentrations of < 30% by weight, based on the weight of the gas phase, d) recirculation of the solvent phase obtained in step c) to the phosgenation in step a), e) introduction of the gas phase obtained in step c) into an absorption in which the phosgene present in the gas phase is absorbed in the same solvent which is also used in the phosgenation in step a), giving a phosgene solution having a concentration of 20-80% by weight of phosgene, based on the weight of the phosgene solution, f) recirculation of the phosgene solution obtained to the phosgenation in step a).