During lung infection Mycobacterium tuberculosis (Mtb) resides in macrophages and subverts the bactericidal mechanisms of these professional phagocytes. In this work we have analyzed by DNA microarray technique the global transcription profile of Mtb infecting primary human macrophages in order to identify putative bacterial pathogenic factors that can be relevant for the intracellular survival of Mtb. Keywords: time course We compared the global gene expression of the H37Rv strain of Mtb after 4 hours and 24 hours of infection of human macrophage-like THP-1 cells with the gene expression profile of the strain growing exponentially in broth cultures.