The present study was designed to evaluate the usefulness of plasma gastrin determinations as a diagnostic aid and to review the clinical and haematological findings in cattle with bleeding abomasal ulcers. Twenty-nine cows with bleeding abomasal ulcers and six healthy cows were used. Clinical and laboratory examinations, including plasma gastrin levels, were performed. Anorexia, depression, dark-coloured to black faeces, pale mucous membranes, abdominal pain, moderate tachycardia and tachypnoea were the most pronounced clinical symptoms in the cattle with bleeding abomasal ulcers. Plasma gastrin concentration was significantly higher (P < 0.05) in the cattle with bleeding abomasal ulcers than in healthy cows. The mean plasma gastrin concentration in healthy cattle was 103.2 pg/ml, while the mean plasma gastrin concentrations in cattle with bleeding abomasal ulcers were found to be 213.6 pg/ml. Haemoglobin levels, packed cell volume, total white blood cell count and mean corpuscular volume were significantly lower (P < 0.05) in the cows with bleeding abomasal ulcer than in the healthy cattle. The results of this study show that measurement of plasma gastrin can be useful in the diagnosis of bleeding abomasal ulcers in cattle.