The objective of this paper was to identify features of some selected sweeteners: aspartame, acesulfam K, sodium cyclamate, and saccharinate. There was assessed the intensity of sweetness of model water solutions, which varied in their concentration levels of intensely sweetening substances contained in them; these model solutions were compared with the standard solutions of saccharose. It was determined what solutions corresponded to the same sensory impressions in terms of the intensity of their sweetness. Furthermore, it was stated that the sweet taste intensity of intensely sweetening sweeteners decreased along with the increase in their concentration levels in a solution. At too high concentration levels of sweeteners in their water solutions, the intensity of feeling the sweet taste decreased, and, at the same time, there was found a lower precision of the assessments performed. The sweetness intensity of sweeteners investigated in their water solutions was easily recognizable and differentiated by the assessing team within a concentration range from 0.035 to 0.085% as for aspartam and acesulfam K, from 0.04 to 0.066% as for sodium saccharinate, and from 0.23 to 0.38% as for sodium cyclamate. There were determined dependences between the sweetness intensity of saccharose and the investigated sweeteners, equivalent in terms of their sweetness intensity, which could be useful for the purpose of quick and simple conversion of their amounts in the case of using them as substitutes of saccharose.