OBJECTIVE: To compare values of urodynamic measurements of cats with idiopathic cystitis (IC) with previously published data for healthy female cats. ANIMALS: 11 female cats with IC. PROCEDURES: 2 sequential cystometrograms and 2 urethral pressure profiles were obtained for each cat. All tracings were evaluated for evidence of overactive urinary bladder (OAB). Maximum urethral pressure (MUP), maximum urethral closure pressure (MUCP), and functional profile length were recorded. RESULTS: Only 3 cats had obvious micturition events. None of the 11 cats had evidence of OAB. Although not significant, threshold pressure was lower in cats with IC than in healthy cats (mean ± SD, 89.0 ± 12.0 cm H(2)O vs 75.7 ± 16.3 cm H(2)O, respectively); however, the total volume infused was significantly lower in cats with IC (4.8 ± 2.1 mL/kg vs 8.3 ± 3.2 mL/kg). The MUCP was significantly higher in cats with IC than in healthy cats (158.0 ± 47.7 cm H(2)O vs 88.9 ± 23.9 cm H(2)O, respectively). The MUP was also significantly higher in all portions of the urethra in cats with IC. CONCLUSIONS AND CLINICAL RELEVANCE: No evidence of OAB was identified in any cat evaluated; therefore, medications used to target this abnormality did not appear justified. The high MUCP in cats with IC suggested that α(1)-adrenoceptor antagonists or skeletal muscle relaxants may be useful in this disease, and if these data were applicable to male cats, then α(1)-adrenoceptor antagonism may help prevent recurrent obstructive IC. Further studies are indicated to determine the effects, if any, these drugs might have in cats with IC.