Recent work implicates Toll-like receptor (TLR) proteins as regulators of innate immune cell activation induced by Mycobacterium tuberculosis, which continues to ravage nearly one-third of the world's population. Novel insights into how TLR proteins may dictate the nature and extent of cellular immune responses against this pathogen will be discussed. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.