Traumatic ruptures of enlarged spleen in the course of haematological conditions are very rare. A case of 51-years old male suffering from a low-grade malignancy non-Hodgin lymphoma, who sustained a rupture of his massively enlarged spleen as a result of blunt trauma of the left side of abdomen and chest is reported. The patient attended to the hospital three days after trauma because of abdominal pain and weakness. Investigations revealed parenchymal laceration of massively enlarged spleen, heamoperitoneum, moderate anaemia and thrombocytopenia 48 G/l. Laparotomy was performed the next day after admission, after preparing packed red blood cells and packed platelets. Massively enlarged, 2.6 kg weight, ruptured spleen was removed and post-operative course was uneventful. Authors consider a reasonable the decision on delayed operation, when no signs of active intra-abdominal bleeding were observed. It allowed to prepare optimal conditions for potentially difficult splenectomy.