Aim: The present study was designed to explore the ability of bone marrow derived mesenchymal stem cells (BM-MSCs) to repair diethylnitrosamine (DEN)-induced liver cirrhosis (DILC) in rats. Materials and methods: Sixty male rats were divided into four groups (15 rats per group), the rats of the first group received saline, and the rats of the other three groups received DEN in drinking water. After thirty days, the rats of the third and fourth groups received 1.5x106 and 2x106 MSC infusions ,respectively. Liver function tests were estimated in serum of rats in all groups. The expression of albumin (Alb) and cytokeratin-18 (CK-18) genes were detected by reverse transcription-polymerase chain reaction (RT-PCR). Histopathological examination of liver tissue was performed. Results: Administration of BM-MSC of both doses (1.5x106 and 2x106 cells) into rats with DILC resulted in ameliorating liver functions and histopathological features compared to that received DEN only. RT-PCR analysis revealed that the expression of albumin gene increased, while CK-18 decreased in liver tissue of rats with DILC which received 2x106 BM-MSCs compared to DEN control group. Conclusion: BM-MSCs suppressed DEN-induced liver cirrhosis in rats as indicated by up regulation of albumin and CK-18 genes, as well as improvement of liver functions and architecture.