AIM: To analyse the fi ndings in a newborn (36 gestational weeks, birth weight: 4,030 grams, birth length: 48 cm, Apgar score 7/8/8 points) with prenatal suspicion of intestinal obstruction at the duodenum/jejunum level. The patient required urgent surgery on the fi rst day of life. RESULTS: Examination of the abdominal cavity confi rmed the presence of a cystic mass with a volume of approximately 800 ml, which was located at the site of jejunal atresia. As part of the surgical solution, the cystic formation and the atretic segment of the intestine were resected with subsequent end-to-end jejunojejunal anastomosis and Bishop-Koop ileostomy. The histological examination of 3 samples collected confi rmed the presence of mucous membrane and smooth muscle. CONCLUSION: The cyst anatomically communicated with the aboral section of the jejunum, but the lumen of the jejunum was functionally obturated by solid whitish masses. The histological examination confi rmed the diagnostic features of a cyst of intestinal origin. The ileum and colon were patent throughout, but of smaller diameter, so a Bishop-Koop relieving anastomosis was indicated. The condition of the child at the age of 9 months was stabilised and surgical closure of the stoma was carried out (Tab. 1, Fig. 8, Ref. 21).