Despite the use of increasingly specific immuno­suppressive therapy, rejection remains the leading cause of death in cardiac transplant patients. Rejection is the leading cause of mortality in the first year after transplantation, and accounts for approximately 20% of all death .End myocardial biopsy already is the gold standard for early detection and monitoring of cardiac rejection However, the approach is invasive and not suitable for routine use.An understanding of the nature and effects of rejection is handicapped by diversity of opinions about the appropriate definition. Rejection has been classified variously as histological, functional and clinical. Regardless of their definitions in academic textbooks, threshold should be very low, even nonspecific symptoms may actually herald onset of rejection. Rejection is an ongoing process that is suppressed, modified and ameliorated by immuno­suppressive drugs. Eventhough biopsy still is the gold standard in follow up survival of this group of patients , but one should consider that biopsy result can be misleading if specimen not obtained and not interpreted in an appropriate manner. There are widespread investigations around the world to find another safer, noninvasive, and less expensive and also as sensitive and specific as biopsy. In this way, we think combined simultaneous measuring of serum cyclosporine level, CD4/CD8 ratio and echocardiography in follow up survival can reduce the frequency of and more advisable endomyocardial biopsy . In other words, the aim of our study was to respond below question. Is there any correlation between serum cyclosporine level, CD4/CD8 ratio, echocardiography and endomyocardial biopsy results? This study have been performing in Imam Khomeini Tehran university hospital on our last 32 (6 female and 26 male, with mean age of 42± 9 yo) patients since January 2007 to September 2008 who underwent orthotopic bicaval heart transplantation during 20 months follow up as yet . The most common indication for transplantation was advanced intractable nonresponsive heart failure due to idiopathic dilated cardiomyopathy. Blood sample was obtained to measure serum cyclosporine and CD4/CD8 ratio 2 weeks after transplantation just before discharge and simultaneous echocardiography and endomyocardial biopsy. This sequence was repeated 2 weeks after discharge again and results were recorded in files. Biopsy result was according to ISHLT standardized cardiac biopsy grading, acute cellular rejection, 2004. Echocardiography was also performed by the same well-experienced cardiologist.