A process for preparing an aqueous surfactant concentrates

The invention concerns aqueous surfactant concentrates having a solids content of between 35 and 65 wt % and containing: (a1) alkyl oligoglycosides and/or alkenyloligoglycosides; and/or (a2) fatty acid N-alkylpolyhydroxyalkylamides; and (b) betaine, in weight ratios of (a):(b) of between 10:90 and 90:10. The pH of these concentrates is in the range of between 3.5 and 6.5. The concentrates are low-viscosity, are free of cloudiness and are stable during storage.