There is no information about the prevalence of gastric ulceration in donkeys or potential risk factors for its presence in donkeys. The donkey is a stoic, hardy animal that has not previously been thought to suffer from this disease. However, gastric ulceration was found to be a problem in a population of non-working UK donkeys resident at the Donkey Sanctuary and its prevalence was estimated by examining necropsy data over a 2-year period during 2005 to 2006. Associations with clinical and management factors were determined. In total, 426 donkeys were examined at necropsy to determine the presence of gastric ulceration. Lesions were described and scored according to a four-point scale. Management and clinical data from these donkeys were analysed to identify potential risk factors for the presence of gastric ulceration. Terminal blood samples were also studied to determine whether animals were exhibiting hyperlipaemia prior to death. Results showed that 41% (n = 174) of the donkeys studied had evidence of gastric ulceration at necropsy. Most (49%) of the ulcers were of a medium size (area of xs2A7E2 cm2 – <10 cm2) and the most common site for ulcers was the margo plicatus. Of the donkeys examined, 18% had hyperlipaemia prior to or death or euthanasia and this was a risk factor for donkeys developing gastric ulceration; 62% of hyperlipaemia cases also displayed gastric ulceration (P < 0.001). Kidney disease was a potential risk factor (P = 0.02), with 74% of these animals having gastric ulceration. Donkeys that died or were euthanased due to respiratory disease were at a decreased risk of developing ulceration (P = 0.01) Donkeys fed a carbohydrate-based diet were more likely (P < 0.001) to have gastric ulceration than those fed a fibre-only diet, with 55% having gastric ulceration compared with 33% in the fibre-only group. This study has shown that gastric ulceration is commonly observed in donkeys at necropsy and may be extensive.