AIDS-related multidrug-resistant tuberculosis (MDRTB) emerged during the 90s in several countries around the world. In Argentina, the most notorious outbreak was documented in the Hospital Muñiz, which is still undergoing its aftermaths. In order to evaluate the situation in this hospital regarding MDRTB, we analysed clinical, demographic and epidemiological traits of the 53 male MDRTB-aids patients admitted during 2001-2003 at a ward especially dedicated to their isolation. Patients' mean age was 32 years, 70% lived in Buenos Aires suburbs. A history of illicit drug users or imprisonment was recorded in 68% and 26% of the patients, respectively. Severe immunodepression (CD4+ count < 100/microl) was found in 88% of the patients and 58% died. Mortality was associated with non-adherence to treatment and co-morbidity, but not with the genotype of the "M" strain, responsible for the original outbreak. Of 40 cases available for restriction fragment length polymorphism (RFLP), 29 (72.5%) resulted in cluster. RFLP patterns of 24 matched the "M" genotype. In this study, resistance to 5 or 6 drugs was found to be an indicator of disease due to the "M" strain. The "M" genotype associated significantly to previous admission at the Hospital Muñiz or imprisonment. In brief, 14 years after the detection of the first MDRTB-aids case, we report here the persistence and predominance of the original outbreak strain at the hospital. Stronger TB infection control measures are urgently needed in hospitals and jails in order to strengthen the declining trend of the MDRTB observed in our country towards the end of the last decade.