ABSTRACTNatural transformation plays an important role in the formation of drug-resistant bacteria. Exploring the regulatory mechanism of natural transformation can aid the discovery of new antibacterial targets and reduce the emergence of drug-resistant bacteria. Competence is a prerequisite of natural transformation inStreptococcus pneumoniae, in whichcomCDEoperon is the core regulator of competence. To date, only ComE has been shown to directly regulatecomCDEtranscription. In this study, a transcriptional regulator, the catabolite control protein A (CcpA), was identified that directly regulatedcomCDEtranscription. We confirmed that CcpA binds to thecis-acting catabolite response elements (cre) in thecomCDEpromoter region to regulatecomCDEtranscription and transformation. Moreover, CcpA can coregulatecomCDEtranscription with phosphorylated and dephosphorylated ComE. Regulation ofcomCDEtranscription and transformation by CcpA was also affected by carbon source signals. Together, these insights demonstrate the versatility of CcpA and provide a theoretical basis for reducing the emergence of drug-resistant bacteria.IMPORTANCEStreptococcus pneumoniaeis a major cause of bacterial infections in humans, such as pneumonia, bacteremia, meningitis, otitis media, and sinusitis. Like most streptococci,S. pneumoniaeis naturally competent and employs this ability to augment its adaptive evolution. The current study illustrates CcpA, a carbon catabolite regulator, can participate in the competence process by regulatingcomCDEtranscription, and this process is regulated by different carbon source signals. These hidden abilities are likely critical for adaptation and colonization in the environment.