Abstract: Objective To observe the therapeutic effect of human umbilical cord Wharton's jelly mesenchymal stem cells (WJMSC) transplantation on ischemic cardiac disease. Methods Thirty patients with cardiac insufficiency due to ischemic heart disease admitted to Chinese PLA General Hospital from December 2010 to January 2012 were randomly divided into treatment group and control group (15 in each group). WJ-MSC(2×10⁷) were prepared. Patients in treatment group underwent coronary arteriography and 10 ml MSC (2×10⁷) suspension transplantation. Those in control group underwent coronary arteriography and were injected with 10 ml 0.9% sodium chloride. Safety of treatment was observed according to their ECG and laboratory test, their heart function was assessed according to the UCG, their quality of life was assessed according to the SF-36 health scale 3 and 6 months after operation.Severe adverse clinical events were recorded. Results No significant difference was observed in laboratory test and adverse clinical events during the treatment and follow-up periods between the two groups. The LVEDV and LVESV were significantly lower whereas the LVEF was significantly higher in treatment group than in control group 3 and 6 months after operation than before operation (P< 0.05). No significant change in LVEDV, LVESV and LVEF was observed in control group (P> 0.05). The scores of physical function and general health were significantly increased in the two groups 3 and 6 months after operation than before operation (P< 0.05), which were significantly higher in treatment group 6 months after operation than in control group 3 months after operation (P< 0.05). A significant difference was found in the general health scores between the two groups (P< 0.05). Conclusion Coronary WJ-MSC transplantation can improve the cardiac function in patients with ischemic heart disease and is thus a safe and effective treatment modality for ischemic heart disease.