BACKGROUND: We report the rare case of a chorioretinitis occurring after intravesical BCG instillation to cure in situ carcinoma. HISTORY AND SIGNS: A 57-year-old man was treated for bladder carcinoma with BCG instillations. Visual acuity was 20/20 in the right eye and 20/40 in the left eye. Bilateral chorioretinitis was discovered three months after initiation of intravesical BCG therapy. THERAPY AND OUTCOME: No progression of ocular lesions could be seen after a 6 months therapy with rifampicin, isoniazide and ethambutol. CONCLUSIONS: BCG chorioretinitis is a rare complication that can be seen after intravesical BCG therapy. BCG is a live attenuated strain of Mycobacterium bovis. Two mechanisms can be proposed as the origin of ocular inflammation: a local immune response or a direct choroidal mycobacterial infection.