BACKGROUND Damages to the small intestinal wall resulting from ischemic-reperfusion changes, represent common complications of the clinical transplantation of the small intestine. OBJECTIVE Evaluation and quantification of the histological changes in the jejunal wall following its autotransplantation in a dog using the scale according to Park. METHODS In dogs (n = 8), mongrel of both sexes, aged from 6 months to 2 years, weighting from 10 to 25 kgs, a resection of the jejunum followed by its autotransplantation was performed. At the time of the jejunal harvest, then after one-hour-long cold ischemia, 20 minutes after its reperfusion and then the 10th and the 20th day after the transplantation, bioptic samples of the whole jejunal wall were taken to be examined histologically. After being stained with hematoxyllin-eosine, the samples were evaluated according to the Park grading system. METHODS The severity of the jejunal wall damage at the respective biopsy samples collection times was evaluated using the t-test for two dependent samples. RESULTS After an hour-long cold ischemia, signs of increasing damage to the intestinal wall were observed, when compared to the peroperative sample (0 +/- 0) up to the degree 0.68 +/- 0.5 of the Park grading schema (p < 0.05). This damage degree increased 20 minutes after the reperfusion up to the value of 4 +/- 0 (p < 0.05). On the 10th and the 20th day a practically normal histological picture of the jejunal wall was observed. The histological changes in both cases were graded 0.38 +/- 0.5 (p < 0.05). CONCLUSIONS Maximum histological changes following the autotransplantation of the small intestine with an hour-long cold ischemia were observed 20 minutes after the reperfusion. After 10 postoperative days, a practically normal histological picture of the small intestinal wall structure was observed. It remained unchanged even on the 20th postoperative day.