Although Streptomyces coelicolor is not resistant to tellurite, it possesses several TerD domain-encoding (tdd) genes of unknownfunction. To elucidate the function of tdd8, the transcriptomes of S. coelicolor strain M145 and of a tdd8 deletion mutant deriva- tive (the Δtdd8 strain) were compared. Several orthologs of Mycobacterium tuberculosis genes involved in dormancy survival were upregulated in the deletion mutant at the visual onset of prodiginine production. These genes are organized in a putative redox stress response cluster comprising two large loci. A binding motif similar to the dormancy survival regulator (DosR) bind- ing site of M. tuberculosis has been identified in the upstream sequences of most genes in these loci. A predicted role for these genes in the redox stress response is supported by the low NAD+/NADH ratio in the Δtdd8 strain. This S. coelicolor gene cluster was shown to be induced by hypoxia and NO stress. While the tdd8 deletion mutant (the Δtdd8 strain) was unable to maintain calcium homeostasis in a calcium-depleted medium, the addition of Ca2+ in Δ tdd8 culture medium reduced the expression of several genes of the redox stress response cluster. The results shown in this work are consistent with Tdd8 playing a significantrole in calcium homeostasis and redox stress adaptation.