Vegetable contains all indispensable necessary mineral salts for metabolism in human's organism. In Croatia, vegetable production has a rich tradition and it is developed in different, mostly favourable agroecological conditions. Chicory is usually consumed as fresh vegetable. Because of a high content of inulin, it is important vegetable in diabetic nutrition. Beetroot is grown because of thickened root and it is considered as a medicine for anemia. Potassium in soil originates from primary minerals such as feldspars. It becomes available to a plant after mineral decomposition. Mechanism of potassium uptake normally works only with the enough amount of water and oxgyen in the soil. Potassium activates enzymes. Insufficient entry of potassium into human's organism by food can rarely cause its deficiency. Symptoms of potassium lack include weakness and muscles convulsion, EKG abnormalities, fatigue and other. Daily need for potassium among adults is from 2000 to 2500 mg. The aim of this paper was to determine the potassium content in samples of beetroot and chicory. Sampled vegetables are produced in a conventional and organic way. Samples are dried on 105 °C and after that crushed and homogenised. Potassium is after the digestion with concentrated HNO3 and HClO4 in microwave owen, determined on a flamephotometer. Dry matter is determined by gravimetry, drying until the constant mass. The highest dry matter content in beetroot (13,44%) was determined in a sample grown in an ecological way, while the highest dry matter content in chicory (7,30%) was deterined in a sample grown in a conventional way. The highest potassium content in fresh matter was determined in samples grown in a conventional way. In beetroot, the highest potassium content was 540,96 mg K 100 g-1 fresh matter, and in chicory 352,24 mg K 100 g-1 fresh matter.