In paper a results of oxygen concentration and redox potential measure-ments are presented. The analyses were conducted in annual cycle in four lakes of Suwalsko-Augustowskie Lakelands. The four lakes - Studzieniczne, Białe Augus-towskie, Rospuda Augustowska and Necko - situated in the immediate vicinity of Augustow city were taken into cosideration. Measurements were carried out with use of multiparameters probe YSI 600Xl in about monthly intervals since May 2006 to April 2007 in control point with a largest depth. Obtained results have confirmed the eutrophic character of analysed lakes as well as significant role of internal feeding in process of their eutrophication.