Ribosomal proteins not only act as components of the translation apparatus but also regulate cell proliferation and apoptosis. A previous study reported that MRPL41 plays an important role in p53-dependent apoptosis. It also showed that MRPL41 arrests the cell cycle by stabilizing p27Kip1 in the absence of p53. This study found that MRPL41 mediates the p21WAF1/CIP1-mediated G1 arrest in response to serum starvation. The cells were released from serum starvation-induced G1 arrest via the siRNA-mediated blocking of MRPL41 expression. Overall, these results suggest that MRPL41 arrests the cell cycle by increasing the p21WAF1/CIP1 and p27Kip1 levels under the growth inhibitory conditions.