Aim of this study is to clinically, microbiologically and histopathologically characterize inflammatory bowel disease (IBD) in the cat. Nine cats with chronic persistent or intermitent vomitus and diarrhea were examined between 1998 and 2001. All cats had a thuorough diagnostic workup performed. Full thickness biopsies from stomach, duodenum, jejunum, ileum and colon were surgically obtained for histopathological examination. Duodenal juice was obtained by direct aspiration for microbiologic qualitative and semiquantitative examination. Seven cats euthanized for other medical reasons were used as controls. Six cats had a lymphoplasmacytic IBD and three an eosinophilic IBD. Four cats with IBD had additional diseases diagnosed. Three cats with IBD had elevated bacterial counts. Retrospectively no correlation could be found between clinical symptoms and histopathological results. Serum TLI was not able to differentiate chronic pancreatitis and IBD. Serum folic acid and cobalamin did not correlate with the distribution of lesions in the gastrointestinal tract. Finally, no correlation was found between bacterial counts in the proximal duodenum and IBD.