Background: Granulomatous prostatitis is an uncommon inflammatory process of the prostate, which in most cases, is nonspecific. Clinical presentation, treatment, and evolution are similar to those of benign prostatic hypertrophy, but this lesion is also a clinical mimicker of prostate. Fungal granulomatous prostatitis is rare and there are only a few reported cases. Clinical case: We report the case of a patient diagnosed with prostatitis blastomycosis. The patient had obstructive and irritative lower urinary tract symptoms, which showed slight improvement the first days of medical treatment. Finally, he underwent transurethral resection of the prostate due to the persistence of the obstructive symptoms. Results: The histopathologic result showed granulomatous prostatitis with features of blastomycosis fungal structures. Diagnosis was confirmed through molecular biology techniques. Conclusion: Despite its low incidence, the diagnosis of fungal granulomatous prostatitis is important to keep in mind, because it can mimic other prostatic pathologies.