The authors report a case of cystitis due to Toxoplasma Gondii infection in a patient suffering from AIDS. Initial symptoms consisted of dysuria, extreme frequency and urgent micturition responsible for pseudo urinary incontinence. Urine culture was sterile. Pelvic computed tomography and pelvic MRI demonstrated thickening of the bladder wall and seminal vesicles. Cystoscopy confirmed the presence of an intravesical proliferation with a pseudoneoplastic appearance. The diagnosis of Toxoplasma cystitis was confirmed by the discovery of Toxoplasma cysts on histological examination of bladder biopsies. Toxoplasma cystitis is a rare cause of pseudoneoplastic bullous cystitis in HIV-seropositive patients.