Abstract: The present invention relates to an aqueous concentrate of an associative thickening polymer, the concentrate containing a nonionic surfactant as viscosity-reducing agent. The nonionic surfactant is water-soluble and has the formulaRO(--AO--).sub.(a) H (1)wherein R is an alkyl group having 6-12 carbon atoms and AO is an ethyleneoxy or propyleneoxy group, the ratio of the ethyleneoxy groups to the total number of ethyleneoxy and propyleneoxy groups being from 1:2 to 5:6, and a is a number between 7 and 16. The presence of a small amount of the nonionic surfactant results in a surprisingly great reduction of the viscosity, which permits the formulation of concentrates having high percentages of the associative polymer without negatively affecting the properties when the concentrate is used for thickening purposes.