We present herein on two cases of fungal rhinosinusitis infiltrating the adjacent structures. The first case was zygomycosis in the sphenoid sinus infiltrating the superior orbital fissure and clivus, developed in an old but immunocompetent female. Endoscopic sinus surgery followed by systemic administration of liposomal amphotericin B (L-AMB) rapidly relieved the symptoms of severe headache and high fever. The accompanying abducens palsy also recovered 3 months after the treatment. The second case was aspergillosis extending into the orbit and cavernous sinus in a 66 years old male with diabetes mellitus. While L-AMB treatment showed limited effect, alteration to voriconazole and micafungin administration dramatically improved the signs and symptoms. Oral administration of voriconazole was continued for 4 months until negative serum βD glucan confirmed. These two cases were successfully treated with endoscopic surgery and antifungal agents, but invasive fungal rhinosinusitis remians a challenging clinical state for otolaryngologists. Treatment plans should be based on the histological identification of the causal fungus.