The objective of the research was determination of artificial sweeteners: aspartame, acesulfame-K and sodium saccharin in eight dietetic beverages (five diet colas, two energetic drinks and one orange beverage) which were purchased from local market in Szczecin in the first three months of 2006. The content of the sweeteners in beverages were measured by high-performance liquid chromatography (HPLC). This procedure was based on isocratic, chromatographic separation on reversed-phase column C18 with phosphate buffer solution 0,02 mol/l (pH 4,3) containing 10 % (v/v) acetonitrile as the mobile phase, and ultraviolet (UV) absorbance detection. Aspartame, acesulfame-K and sodium saccharin content were below the upper limits of their permitted norms for soft drinks in determinated dietetic beverages. The highest levels of aspartame (585,87 mg/l) and acesulfame-K (187,13 mg/l) were detected in branded beverages, which did not contain in their composition sodium saccharin. Whereas 75% non-branded beverages were characterized by high content of sodium saccharin. Moreover, the presence of aspartame in one of them was not noticed, although the sweetener was numbered as an ingredient in this product. In about 87,5% of products under study aspartame and acesulfame-K were identified while only 50% of the ones contained sodium saccharin.