Introduction. Meckel’s diverticulum is a remnant of vitelline duct in the distal ileum, that is found in 23% of the population. The main problem in diverticulum is its non-specific symptomology and difficult diagnostics. According to different sources an average of 5% of patients with Meckel’s diverticulum may develop complications, including perforation, hemorrhage, diverticulitis, and malignancy. Perforation presents one of the most sudden and dangerous complications, that can mimic other conditions. Case presentation. Patient P, a 41-years-old man, was admitted urgently to the Department of Surgery, Municipal Hospital nr.1, with bloating and abdominal pain that appeared 3 hours before hospitalisation, nausea, weakness. Physical examination revealed a painful bloated abdomen, that doesn’t participate in respiration, pain intensity maximises in right iliac fossa. Laboratory tests revealed high levels of WBC – 12.2 x10⁹/mm3, with shift to the left (band cells – 9%), low lymphocytes – 13%. Based on symptomology and laboratory tests acute appendicitis was suspected, and urgent surgery is indicated. During the intervention 8 cm McBurney incision was performed. At revision of abdominal cavity seropurulent discharge in volume of 10 ml was found, and edematous vermicular appendix 7x1cm, located retrocecal, retroperitoneal. Appendix was removed. After that at the distance of 60 cm from the ileocecal valve was found Meckel’s diverticulum, perforated with foreign body (fish bone). Diverticulum had phlegmonous changes and fibrin plaques. Cuneiform resection of diverticula was performed. Small pelvis drainage and surgical wound dressing with aseptic bandage were performed. Macro- and microscopic description: Intestine segment is blind at the one end. Is similar to diverticulum. D = 4.7 x 2.8cm. Dark grey colour, covered in pale grey fibrinous masses. Discussion. This case was selected due to its diagnostic value and ambiguity of the clinical picture. Based purely on symptoms acute appendicitis was suspected and later confirmed, but the basic diagnosis and cause of acute appendicitis was perforation of Meckel’s diverticulum, that wasn’t suspected at the moment. This case shows the problems that specialists encounter with this pathology and the importance of preoperative and intraoperative diagnostics. Conclusion. Meckel’s diverticulum is a rare condition, which is difficult to diagnose, due to its unspecific symptomology and high percentage of asymptomatic cases. Mostly they are discovered intraoperative or after the appearance of complications, that can have drastic or even fatal consequences.