Carbamatoorganosilanes are produced in exceptionally high yield with a high degree of purity, by reacting an aminoorganosilane with a dialkylcarbonate in the presence of a basic catalyst, wherein a first reaction period proceeds at a temperature in the range of 35-65° C., followed by a later reaction period at a temperature at least 10° C. higher. A low level of catalyst allows its removal by simple exit filtration, without a separate filtration step.