Objective: Stem cell therapy may offer new hope in the management of cirrhosis. One of the potential complications of stem cell therapy is tumor development. Recently, a case of donor-derived brain tumor has been reported after transplantation of neural stem cells (Amariglio N, et al. PLoS Medicine 2009). There is no long term follow up study in regard to the tumor development in cirrhotic patients who underwent stem cell transplantation. we aim to report the data related to the tumor development in our three prospective trials of autologous stem cell transplantation in liver cirrhosis. Materials and Methods: Data of serum alfa-fetoprotein (AFP) levels, abdominal ultrasound, and abdominal CT scan at baseline and at the end of follow up were assessed from the databank of the following prospective trials.A phase 1 trial(1) in which the mean number of 7 milion CD34+ hematopoietic BM stem cells were infused through hepatic artery in 3 patients with cirrhosis. Another phase 1 trial(2)in which the mean number of 31 milion mesenchymal stem cells (MSC) were infused through peripheral vein in 4 patients. A phase 2 trial(3) in which the mean number of 400 milion MSC were infused through peripheral vein in 8 patients. The last study is an ongoing randomized controlled trial, which the data of the treatment arm is presented. Serum AFP levels, and abdominal ultrasonography were done every 6 months for all the patients. Also, all of them had baseline CT scan, and follow up CT scan at 6 months of post-transplantation. All the patients were on the waiting list of liver transplantation. Results: A total of 15 patients (6 men) were evaluated. Mean age of the patients was 45.1 (± 14.9). Mean duration of follow up was 23.5 (±9.7) months. Mean serum AFP was 2.8 (± 1.9) mcg/L at baseline, and 4 (± 1.5) mcg/L at the end of follow up (p> 0.05). No evidence of liver tumor, or other intra-abdominal tumors was found in the 15 studied patients during the study period. Four out of 15 patients (e.g. 26.7%) died due to complications of cirrhosis during the follow up. None of the patients underwent liver transplantation. Conclusion: In this long term follow up study, we found no evidence of tumor development in cirrhotic patients who underwent autologous BM stem cell transplantation.