Invasive aspergillosis in solid organ transplant recipients is associated with mortality of approximately 100%. The search for optimal therapy has led clinicians to administer antifungal combinations. Two orthotopic liver transplant recipients developed invasive aspergillosis (pulmonary and perivertebral) after transplantation and were treated with combination antifungal therapy consisting of liposomal amphotericin B and itraconazole. Although both patients were initially stabilized, they died after 94 and 138 days of antifungal therapy, respectively. Presumably, aspergillosis was the principal cause of death. Antifungal serum concentrations and fungicidal titers in both patients indicated that the drugs may have been antagonistic and thus detrimental.