In spite of great progress in understanding cancer biology, current therapeutic procedures remain unsatisfactory. Chemotherapy is often followed by secondary effects with cellular toxicity negatively affecting the results. The discovery and development of new safe and efficient antitumor agents is necessary. Derivatives of 2-amino thiophene have been a topic of constant investigation due to their versatile synthetic applicability and broad spectrum of biological applications; among which are antifungal and antiproliferative activity shown in prior studies of our group. In the current study, compounds 6CN09, 6CN10, 6CN12, 6CN14, 7CN09 and 7CN11 were analyzed as to antiproliferative effect in human cells of cervical adenocarcinoma (HeLa), human pancreatic adenocarcinoma (PANC-1) and mice fibroblasts (3T3), which were exposed to the compounds in concentrations of 5, 10, 25 and 50μM during 24 and 48h. They were submitted to MTT assay. In order to elucidate the action mechanism of antitumor thiophene derivatives flow cytometry was performed to evaluate cell death and cell cycle analysis. The results showed that thiophene derivatives demonstrated great antiproliferative potential in the HeLa and PANC-1 cell lines when compared with the control, and the percentage of cell proliferation inhibition approximated or was higher than the standard drug used; doxorubicin (Dox). In highlight were the derivatives 6CN14 and 7CN09 that showed greater efficiency in the antiproliferative evaluation. Further, all compounds had a protective effect on the non-tumor 3T3 cell line. The flow cytometry analysis showed few cells in apoptosis in both the HeLa and PANC-1 lines, although the compounds interfered with the progression of the cell cycle, and avoided cell growth and multiplication in the HeLa tumor line. These thiophene derivatives demonstrated cytostatic and antiproliferative effects and may be considered as promising molecular candidates for anticancer drugs.