The influence of the characteristics (molecular weight, alkyl group composition, ratio of acrylate to methacrylate units) and dosage of poly(alkyl (meth)acrylate) thickening agents on the pour point of various base oils used for manufacturing hydraulic fluids has been studied. It has been shown that the effect of pour point elevation with the increasing additive concentration can be leveled by extending the range of alkyl groups and introducing methyl methacrylate units into the polymers.