OBJECTIVE: Mucormycosis or Zigomicosis is an invasive fungal infection uncommon and, in general, occurs in immunosuppressed, with tax of mortality of 50% 90%. In this story, two cases of RSF in diabetic patients are described, confirmed for histopathology, which disclosed the presence of infection for zygomycota. Case 1: Patient of 66 years, diabetic and renal transplanted, with rhino mucormycosis and clinical suspicion of thrombosis of the cavernous sinus was submitted to the antibiotic treatment, ample endoscopic debridement of the nasal-sinusal mucous and has supported physician in Unit of Intensive Therapy, evolving of sudden form, although the precocious diagnosis and adequate treatment. Case 2: Patient of 28 years, diabetic type 1, without previous glucose control and other co-morbidities, presented mucormycosis rhinocerebral, being submitted to the antibiotic treatment, glucose control and ample endoscopic debridement of the nasal-sinusal mucous. The patient today does not present rhinossinusitis and is followed in the University Hospital Peter Ernesto (HUPE/UERJ), keeping sequels, as nose in saddle, palatal perforation and brad psychism. CONCLUSION: The increase of the supervened one and the prevalence of immunosuppressed patients are raising the incidence of the fungal rhinossinusitis, but the therapeutical one still must be argued and be optimized, to increase the supervened one of this population, a time that this disease has high tax of mortality. Currently, the prognostic more than depends the immunological reply on the host of what of the particular type of fungal that cause the infection and the morbity of that they survive is raised.