Infectious multiresistant pulmonary tuberculosis was diagnosed in a 24-year-old woman from an Eastern European country who resided in the Netherlands illegally. Her chest X-ray showed extensive cavitating lesions in both lungs. The patient was infectious for a long time and contact investigation revealed 2 other cases of multiresistant tuberculosis, her boyfriend aged 39 and his father, aged 58 years. Transmission from the index case was confirmed by DNA fingerprinting. Seven contacts had a latent tuberculosis infection. All 3 tuberculosis patients were successfully treated, while a number of the infected contacts received preventive treatment. Multiresistant tuberculosis is on the rise in Eastern Europe. It is a serious disease with a high mortality rate despite treatment and has considerable social implications. This outbreak emphasises the necessity of maintaining an efficient tuberculosis control network in low incidence countries, such as the Netherlands. This is the first time an outbreak of multiresistant tuberculosis of this magnitude is described in the Netherlands.