The DPB11 gene, which genetically interacts with DNA polymerase II ($varepsilon$) encoded by POL2 and DPB2, is required for DNA replication and the S phase checkpoint in Saccharomyces cerevusiae. The transcripts of DPB11 did not fluctuated as evidently as DPB2 and POL2 genes during cell cycle. To identify the physical interaction between Dpb2 and Dpb11, we examined the interaction by two-hybrid system. The interaction between Dpb2 and Dpb11 was detected in a two-hybrid assay. These results suggest that the amount of the Dpb2-Dpb11 complex may peak at the G1/S boundary. Therefore, we strongly suggest the involvement of the Dpb2-Dpb11 complex in a progression of DNA replication and S-phase checkpoint.