Voriconazole is the drug of choice for invasive aspergillosis. We describe three patients who presented with severe hyponatremia after the initiation of voriconazole treatment. One patient expired while the other two patients recovered after a dose adjustment or discontinuation of the antifungal. The voriconazole trough levels were checked in all and two were elevated. These findings mandate monitoring electrolyte levels during voriconazole therapy.