As part of ongoing efforts to investigate the molecular biology of the human pathogens in the genus Mycobacterium, a customized database was developed specifically for these organisms and implemented in ACEDB database manager software. The data loaded include the IMMYC Antigen List, details of reagents available from the CDC/WHO Antibody Bank, more than 1 Mb of sequences of mycobacterial genes and proteins from public databases, the physical maps of Mycobacterium leprae and Mycobacterium tuberculosis developed at the Institut Pasteur, as well as a subset of the references found in MedLine. The ACEDB software allows both quick and intuitive access to the data and to connections between facts by a simple mouse-driven interface, as well as by more powerful query mechanisms.