P. mirabilis is a common cause of C-UTI. This study evaluates the effect of stearic, plamitic and myristic acids to LB culture medium, on swarming, biofilm formation and EPS production of 30 P. mirabilis strains isolated from 300 urine samples collected from 300 catheterized patients. Myristic and palmitic acids could inhibit swarming and EPS of P. mirabilis. Only myristic acid could inhibit biofilm formation, while stearic acid enhanced swarming and EPS production of P. mirabilis.