The objective of this study was the validation of selected methods of determining aspartame content, which was performed based on the parameters constituting elements of the analytical validation procedures. From among the basic criteria of validating the analytical method, the following were applied: selectivity, linearity, precision (repeatability), uncertainty of measurement, and accuracy. In addition to those elements of assessing the method, a HORRAT value was also utilized since it appears more and more frequently in the relevant standards. Six methods were taken into consideration: HPLC, three spectrophotometric methods, and two titration methods. Aspartame was determined spectrophotometrically after the reaction with the colouring agents such as N-bromosuccinimide-metol-sulphanilamide, chloranil acid, and p-chloranil. The level of aspartame in tabletop sweeteners was assessed by titrimetry using acetous perchloric acid, sodium metoxide, and N-bromosuccinimide as titrants. HPLC and titration method with perchloric acid were found to be the most precise methods. They were characterized by acceptable values of a relative standard deviation and a HORRAT value.