Objective: The aim of this study was to characterize ultrasonographically detectable mural changes in cats with intestinal disorders and to determine their diagnostic relevance. Material and methods: Ultrasonographical examination was performed between 2002-2005 in 30 cats with non-specific gastro-intestinal symptoms. Alterations of the thickness, layering and echogenicity of the intestinal wall, symmetry and dimensions of the lesion if present, and involvement of abdominal lymph nodes were evaluated. Tissue specimens were collected for histopathologic examination by ultrasound-guided 18-gauge tru-cut biopsy or full-thickness biopsy via laparotomy. Results: Sonographic evaluation of 30 cats revealed a separate thickening of the muscular layer (n = 14) and a symmetric (n = 10) or asymmetric (n = 6) thickening of the entire intestinal wall. Further sonographical findings of the abdomen were enlarged lymph nodes, free fluid and oedema of the mesentery, or additional lesions in other organs. Histopathologically, 12 cats had benign inflammatory disorders, 13 cats had alimentary lymphoma, four cats had adenocarcinoma, and in one case the intestinal tract was histologically normal. Conclusions: Increased thickness of the muscularis propria maintaining normal mural layering occurs more frequently during intestinal inflammation (10 of 12 cases), while neoplastic alterations more often show a symmetric or asymmetric thickening of the entire bowel wall. Clinical relevance: Diagnostic ultrasonography is an important tool for the detection of mural alterations of the intestinal tract in the cat. The definite diagnosis must be made histopathologically.