Monitoring of the quality of the bathing sea is carried out according to the Regulation on the quality of the bathing sea (NN 73/08), and routine microbiological parameters are indicators of fecal pollution (E. coli and intestinal enterococci). Fecal pollution occurs when microorganisms that cause diseases reach the water, and the source of which are human and animal feces and excreta. In addition to routine indicators of fecal contamination, additional microbiological contamination, additional microbiological indicators, such as Pseudomonas aeruginosa, can be tested according to the recommendation of the World Health Organization. Iti s a bacterium ubiquitous in the environment, which causes skin rashes and eye and ear infections after exposure to contaminated water or the sea. The aim of this research was to examine the occurrence and concentration of P. aeruginosa in the bathing sea in the area of urban beaches in the western part of the city of Rijeka (Kantrida), under different environmental conditions. Sampling was carried out on four beaches and six locations: 3. Maj, Kantrida east and west, Nogometno igralište, Ploče east and west. During the research, two samplings were carried out in the period from February 2, 2023. until 27.02.2023. The first occurrence was during the dry season, and the second during the rainy season. In addition, the dana of the additional intensive research conducted in the period from 2012 to 2014, in the same locations, were also processed. The ISO norm HRN EN ISO 16266:2008 was applied for testing P. aeruginosa in seawater sampples. The results of the research showed that the occurrence of P. aeruginosa is significantly influenced by precipitation and freshwater inflows, and that the bathing sea in the area of the city of Rijeka is slightly to moderately loaded with P. aeruginosa. Positive correlation was established between P. aeruginosa and other fecal and non-fecal microbiological indicators. Monitoring of routine indicators (E. coli and enterococci) does not completely exclude the possibility of contact and infection of bathers with P. aeruginosa bacteria. The public health risk of P. aeruginosa infection is increasing, due to the multiple drug resistance of this bacterium and the weakening of the populations immune response.