Abstract: Method for controlling the alumina feed to reduction cells for the production of aluminum. There is employed an adaptive control with parameter estimation (3) and controller calculation (2) based upon the separation theorem. As a process model there is used a linear model having two inputs and one output. One input (u.sub.1) is in the form of alumina feeding minus assumed alumina consumption. Another input (u.sub.2) is in the form of movements of the reduction cell anode. The output (y) is in the form of the change in electric resistance across the reduction cell concerned. The model is of the first order in u.sub.1 and u.sub.2 whereas it is of the order zero in y. An estimated parameter (b.sub.1) represents the slope of the curve for resistance as a function of alumina concentration in the electrolytic bath, and the controller (2) controls the addition of alumina to the electrolytic bath in response to the value of b.sub.1.