Mucormycosis is the third cause of invasive mycosis after candidiasis and aspergillosis in AML patients, representing a poor prognostic factor associated with a high rate of fatal outcome. We report a case of a patient with AML and a concomitant pulmonary mucormycosis at diagnosis, who obtained a complete remission both of her AML and of the fungal infection. The incidence of the infection at the onset of leukemia is extremely unusual, and, to our knowledge, the sporadic cases reported in the literature are included in heterogeneous series retrospectively examined. In our case, Liposomal Amphotericin B as single agent appeared incapable of controlling the infection, so anti-infective therapy was intensified with posaconazole and simultaneously antileukemic treatment with 5-azacitidine was started, with the understanding that the only antifungal treatment would not have been able to keep the infection under control for a long time if not associated with a reversal of neutropenia related to the disease. We observed a progressive improvement of the general conditions, a healing of pneumonia and a complete remission of the leukemic disease, suggesting that a careful utilization of the new compounds available today, in terms of both antifungal and antileukemic treatment, may offer a curative chance a patient who would have otherwise been considered unfit for a potentially curative therapeutic strategy.