Follicular cystitis is a rare bladder disease that is difficult to diagnose due to its non-specific symptoms. The diagnostic is made by biopsies of the affected area, and the anatomopathological study confirms it. The treatment of follicular cystitis is not well established, and more research is needed to determine the optimal treatment protocol. We present a case of a 44-year-old man with a medical history of type 1 diabetes and pulmonary tuberculosis who was diagnosed with follicular cystitis. The patient was treated with corticoids, and the evolution was good. However, it is important to note that the recurrence of cystitis is frequent, and prevention techniques should be followed to avoid urinary infections.