The cause of cystitis in many cats remains unknown. The aim of this study was to determine whether or not any environmental or behavioural factors, particularly those that could be considered potentially stressful, were associated with feline idiopathic cystitis (FIC). The questionnaire-based study involved comparing 31 cats with FIC to 24 cats in the same households that did not have cystitis. They were also compared with a control population of 125 clinically healthy cats. Compared with the live-in controls and the control population, the cats with FIC were significantly more likely to be male, overweight and pedigree. Several stress factors were found to be associated with FIC. The factor that stood out most prominently was living with another cat with which there was conflict. The findings support the hypothesis that stress may be implicated in some cases of FIC.