A 32-year-old immigrant from Pakistan was admitted to our hospital with cavernous pulmonary tuberculosis. He gave a history of several 1 to 2-months courses of antimycobacterial treatment administered earlier in Pakistan. We initiated combined therapy including isoniazid, rifampin, pyrazinamide, and ethambutol. Subsequently, results of susceptibility testing from M. tuberculosis-complex strains isolated before the onset of treatment documented the presence of resistance against both isoniazid and rifampin which may have been primary or acquired drug resistances. During the course of treatment, two additional resistances to pyrazinamide and ethambutol developed which were probably due to the initial therapy with only two active antimycobacterial agents. The emergence of multidrug-resistant strains of M. tuberculosis complex is a world-wide problem. Our case indicates that multiresistance must be considered in every patient presenting with tuberculosis. If there is a strong suspicion of multidrug-resistant tuberculosis, initial treatment with a combination of 5-6 antimycobacterial agents seems advisable until the results of susceptibility testing become available.