Oesophageal cysts are rare congenital anomalies. Most commonly, they are located in the posterior mediastinum, approximately at the level of the distal third of the oesophagus. In most cases, they are diagnosed during childhood as an accidental finding of a symptomatic mediastinal lesion. A CT or MRI, oesophagoscopy and endosonography of the oesophagus are the essential diagnostic methods. In the adulthood, most of the cysts cause problems pushing against the surrounding organs and, therefore, surgical removal is recommended. In this report, a case of a potential complication is described: infection of the oesophageal cyst of the distal part of the oesophagus following a transoesophageal punction. The case resulted in sepsis, which was managed laparoscopically. Entering through the diaphragmatic hiatus,a cyst in the posterior mediastinum was revealed. The cyst was partially resected and its content evacuated. No complications followed. The laparoscopic method is feasible and safe even if the oesophageal cysts are infected. A complete resection of the cyst would be complicated due to a possibility of injuring the oesophagus. A significance of the peroperative oesophagoscopy to verify the oesophagus position in an unclear anatomic situation due to inflammatory infiltration, is highlighted. The above decreases the risk of the oesophageal wall lesion.