A process for the regeneration of a catalyst comprising a titanium containing zeolite as catalytically active material, said catalyst having been used in a process for the preparation of an olefin oxide comprising (i) providing a mixture comprising an organic solvent, an olefin, an epoxidation agent and an at least partially dissolved potassium comprising salt; (ii) subjecting the mixture provided in (i) in a reactor to epoxidation conditions in the presence of the catalyst, obtaining a mixture comprising the organic solvent and the olefin oxide, and obtaining the catalyst having a potassium salt deposited thereon; said process for the regeneration comprising (a) separating the mixture obtained from (ii) from the catalyst; (b) washing the catalyst obtained from (a) with a liquid aqueous system which comprises less than 0.1 wt.-% of compounds with a pKa value of 8 or less and contains at least 75 weight-% water based on the total weight of the liquid aqueous system, wherein the washing is performed at a temperature in the range of from 40 to 90 °C; (c) optionally drying the catalyst obtained from (b) in a gas stream comprising an inert gas at a temperature of less than 300 °C; (d) calcining the catalyst obtained from (b) or (c) in a gas stream comprising oxygen at a temperature of at least 300 °C; wherein the titanium containing zeolite has an MFI framework structure or MWW framework structure. (i) providing a mixture comprising an organic solvent, an olefin, an epoxidation agent and an at least partially dissolved potassium comprising salt; (ii) subjecting the mixture provided in (i) in a reactor to epoxidation conditions in the presence of the catalyst, obtaining a mixture comprising the organic solvent and the olefin oxide, and obtaining the catalyst having a potassium salt deposited thereon; said process for the regeneration comprising (a) separating the mixture obtained from (ii) from the catalyst; (b) washing the catalyst obtained from (a) with a liquid aqueous system which comprises less than 0.1 wt.-% of compounds with a pKa value of 8 or less and contains at least 75 weight-% water based on the total weight of the liquid aqueous system, wherein the washing is performed at a temperature in the range of from 40 to 90 °C; (c) optionally drying the catalyst obtained from (b) in a gas stream comprising an inert gas at a temperature of less than 300 °C; (d) calcining the catalyst obtained from (b) or (c) in a gas stream comprising oxygen at a temperature of at least 300 °C; (a) separating the mixture obtained from (ii) from the catalyst; (b) washing the catalyst obtained from (a) with a liquid aqueous system which comprises less than 0.1 wt.-% of compounds with a pKa value of 8 or less and contains at least 75 weight-% water based on the total weight of the liquid aqueous system, wherein the washing is performed at a temperature in the range of from 40 to 90 °C; (c) optionally drying the catalyst obtained from (b) in a gas stream comprising an inert gas at a temperature of less than 300 °C; (d) calcining the catalyst obtained from (b) or (c) in a gas stream comprising oxygen at a temperature of at least 300 °C; wherein the titanium containing zeolite has an MFI framework structure or MWW framework structure.