Silver nanoparticles (Ag-NPs) with antimicrobial activity are by far the most commercialized nano-compound. However, there is limited information about antitumor potential. Therefore, the present study was aimed to observe the effect of small-dimensional Ag-NPs (20Nm) on human epithelial colorectal adeno-carcinoma (Caco-2) cells. Caco-2 cells were exposed to Ag-NPs with different concentrations (1–15μg/mL) for 24 and 48 hours and cytotoxicity was analyzed by MTT assay and IC50 was calculated. In addition, flow cytometry was used to determine the effect of Ag-NPs on the cell cycle progression and on apoptosis. An MTT assay revealed that following exposure to Ag-NPs the viability of Caco-2 cells decreased, and the viability decreased further with increasing exposure time. The IC50 was 7.85 µg/ml and 4.92 µg/ml at 24 and 48 h respectively after exposure. The flow cytometry technique revealed that Ag-NPs induced a significant increase in the percentage of cells in G1 phase of the cell cycle and of apoptotic cells. In conclusion, Ag-NPs exhibited dose- and time-dependent cytotoxicity, and these results have signposted that Ag-NPs were promising nanoparticles which could be a potential candidate in treating colorectal cancer.