Background Cyclin D3, one of the D type cyclins, has been known as a cell cycle modulator at the GI-S phase. In the present study, we investigated its expression in pancreatic adenocarcinoma in order to elucidate its clinical role. Materials and Methods: We examined cyclin D3 as well as, c)rlin D1 overexpression in 60 pancreatic adenocarcinoma by means of immunohistochemistry. Results. Cyclin D3 overexpression was found in 33.3% (20 cases) of the cases, being more frequently seen in cases showing high Ki-67 labeling index, stage IV moderate- or poor-differentiation, lymph node metastasis and large size and cyclin D1 overexpression. Multivariate logistic analysis independently linked cyclin D3 overexpress;on to tumor size (p = 0.0392) and stage (p = 0.0312). Cyclin D1 overexpression was observed in 41.7% (25 cases) and was related to Ki-67 labeling index, cyclin A overexpression, stage, carcinoma differentiation, lymph none metastasis, tumor size, lymphatic invasion, perineural invasion and retropancreatic invasion. It was independently linked to carcinoma differentiation (p 0.0081), lymph node metastasis (p = 0.0426) and lymphatic invasion (p = 0.0269). Conclusion: These results suggest that cyclin D3, as well as cyclin D1, plays a role in the progression, including cell proliferating activity of pancreatic adenocarcinoma.