The promoter driving expression of the Mycobacterium tuberculosis gene lipF (Rv3487c) had previously been identified as being upregulated by acidic stress. Subsequently a 59 base pair (bp) acid inducible minimal promoter region was isolated in which a putative -10 region was identified. In this study we use mutational analysis to investigate the -10 region of the lipF promoter. Mutations within this region lead to a dramatic decrease of promoter activity, while a mutation outside of this region does not affect promoter activity.