Objective. We aim to describe the first case in the literature of allergic fungal sinusitis (AFS) presenting with hyperprolactinemia due to compression of the pituitary gland. Case Presentation. A 37-year-old female presented with bilateral galactorrhea and occipital headaches of several weeks. Workup revealed elevated prolactin of 94.4, negative pregnancy test, and normal thyroid function. MRI and CT demonstrated a 5.0 × 2.7 × 2.5 cm heterogeneous expansile mass in the right sphenoid sinus with no pituitary adenoma as originally suspected. Patient was placed on cabergoline for symptomatic control until definitive treatment. Results. The patient underwent right endoscopic sphenoidotomy, which revealed nasal polyps and fungal debris in the sphenoid sinus, consistent with AFS. There was bony erosion of the sella and clivus. Pathology and microbiology were consistent with allergic fungal sinusitis caused by Curvularia species. Prolactin levels normalized four weeks after surgery with resolution of symptoms. Conclusion. Functional endoscopic sinus surgery alone was able to reverse the patient's pituitary dysfunction. To our knowledge, this is the first case of AFS presenting as hyperprolactinemia due to pituitary compression.