We present a case of pacer wire thrombus and recurrent pulmonary em boli in pregnancy associated with a permanent pacemaker. Transthoracic echocardiography demonstrated a thrombus attached to the pacer wire at the point where it crossed the tricuspid valve. After the uncomplicated vaginal delivery; thrombolytic therapy was given. This thrombus persisted despite thrombolytic therapy. Consequently, the patient was referred for cardiac surgery. The suspected cause was confirmed during the surgery.