The clinical presentation and response to treatment of cats infected with Tritrichomonas foetus have not been sufficiently described in a large number of pet cats. The aim of this study was to collect and analyze clinical data from pet cats diagnosed with intestinal T foetus infection. Clinical information was collected for 104 cats that tested polymerase chain reaction-positive for T foetus. The most common clinical sign was diarrhea (98%) with a median duration of 135 days (range 1-2880 days). Forty-nine of 83 (59%) cats had diarrhea since adoption. Other clinical signs included anorexia (22%), depression (24%), weight loss or failure to gain weight (20%), vomiting (19%), abdominal pain (9%) and increased appetite (3%). A total of 45 cats had completed treatment with ronidazole, 29 of which (64%) showed a good clinical response to treatment. Sixteen (36%) cats had either partial or no improvement, or a relapse shortly after discontinuation of treatment.