Antiphospholipid syndrome is characterized by the presence of antiphospholipid antibodies resulting in arterial and venous thromboembolism. Apart from primary cases, this syndrome is often associated with autoimmune diseases. Around 50 cases of catastrophic antiphospholipid antibody syndrome have been reported as yet. Authors describe the first case of catastrophic antiphospholipid syndrome associated with gastric cancer. Apart from presenting the clinical case, authors also discuss the possible pathomechanism of this associated disorder including the role of immunological factors, as well as antiphospholipid antibodies.