Countries with a low incidence of tuberculosis have recently been faced with the problem of tuberculosis (TB) in asylum seekers from countries with a high TB prevalence. We report on the tuberculosis case notification rate (TBCNR) in Belgium in 1993, and on the results of active screening in a group of asylum seekers. The TBCNR in Belgium in 1993 increased slightly to 14.9 per 100,000, mainly due to the nonindigenous population. The highest TBCNR (312 per 100,000) was reported among the 26,882 asylum seekers staying in Belgium in 1993. Of all new asylum seekers admitted in 1993, 4,794 agreed to undergo radiographic screening for TB at entry, of whom 123 had a chest radiograph which was suspect. Among the 123, 67 could be further investigated, and, of these, 19 cases (28%) of active TB were detected; this represents a TBCNR of 396 per 100,000 when referred to the 4,794 asylum seekers screened. In addition, 56 asylum seekers with suspect chest radiograph were lost to further investigation. From the present results it appears that: 1) in Belgium, asylum seekers constitute an important risk group for TB, with a TBCNR after screening which is approximately 30 times that in the indigenous population; and 2) there is a deficient follow-up after first screening, generating the risk of transmission of TB within the community. Our recommendations are, therefore, that in all asylum seekers screening for tuberculosis should be mandatory and follow-up of active tuberculosis should be regulated.