We report a case of pseudomembranous colitis that developed in a patient with liver cirrhosis during anti-tuberculosis therapy with rifampicin and isoniazid. The association between rifampicin and pseudomembranous colitis has been controversial; this report, however, supports the association. Colonoscopy performed 3 days after the onset of the pseudomembranous colitis revealed only reddish patches and a few aphthoid lesions, but 4 days later pseudomembranes were apparent. The pseudomembranous colitis was successfully controlled by discontinuation of the anti-tuberculosis agents, along with the administration of lactic acid bacteria, without vancomycin or metronidazole. Possible predisposing factors for the development of pseudomembranous colitis in this patient are also discussed.