Objective: This study aimed at evaluating the in vitro effect of Porphyromonas gingivalis exposure in gene expression of E2F1 (family of transcription factors), cyclin-dependent kinase-1 (CDK11), and inducible nitric oxide synthase (iNOS) of the neuronal cell cycle. Materials and Methods: The culture of neuronal cell line SH-SY5Y was exposed to P. gingivalis ATCC 33277, and the gene expression of E2F1, CDK11, and iNOS was analyzed by using a real-time polymerase chain reaction. Results: It was shown that E2F1, a G1 phase biomarker and transcription factor, was upregulated in neuronal cells exposed to P. gingivalis compared with that in control cells. However, CDK11, a biomarker of G2/M checkpoint and iNOS, was downregulated in neuronal cells exposed to P. gingivalis compared with that in control cells. Conclusions: P. gingivalis can regulate the neuronal cell cycle, as indicated in the E2F1, CDK11, and iNOS gene expression.</p>