Primary cutaneous aspergillosis is rare in premature infants. It requires combined medical and surgical strategies. Liposomal amphotericin B is recommended as first-line therapy, but salvage regimens with others antifungal agents, such as voriconazole, have been reported. Voriconazole’s pharmacodynamics is unknown in this population. We report a case of severe toxicity to voriconazole in a preterm patient with primary cutaneous aspergillosis.