Abstract: The rapid and convenient methods based on conductometric flow injection analysis (FIA) were proposed for measuring sugar content of apple juice and juice of sugar beet root and for measuring total solids content of cow's milk. With the FIA system, all measurements were able to carry out under the same operational conditions of the system, by use of each calibration curve for each sample -apple juice, juice of sugar beet root and cow's milk, respectively. For apple juice and clarified juice of sugar beet root with tannic acid, sugar content estimated from the proposed mehtods agreed with that obtained from phenol-sulfuric acid method with an error of 0.24%. For cow's milk homogenate, the total solids content estimated from the proposed method agreed with that obtained from gravimetric method (method of A.O.A.C.) with an error of 0.19%.