Both non-Hodgkin's lymphoma (NHL) in pregnancy and acute spontaneous tumor-lysis (ASTL) syndrome are rare. Here we present a 32-year-old Egyptian woman in the 27th week of pregnancy, who was admitted with epistaxis, lethargy, vomiting and dehydration. This patient developed ASTL syndrome secondary to undiagnosed NHL, but was not on any medication associated with the syndrome. At 28 weeks, she gave birth to a healthy baby who, unfortunately, died within a few days. To our knowledge, this is the first case of ASTL syndrome in a pregnant woman.