Pericardial effusion has been identified as a rare cause of hyponatremia. In most patients, pericardiocentesis results in rapid correction. We describe a 67-year-old male who presented with pericardial effusion-associated hyponatremia secondary to cardiac resynchronization therapy-D placement that resolved following evacuation. In addition, we review the literature on pericardial effusion-associated hyponatremia.