Post-transplant erythrocytosis (PTE) is increasingly recognized as a complication of kidney transplantation. PTE is defined as a persistently elevated hematocrit to a level greater than 52% after renal transplantation. Thromboembolic events occur in 10% to 30% of the cases; 1% to 2% eventually dies of associated complications. The pathogenesis of PTE remains unknown and may be multifactorial. In a retrospective analysis, among 500 recipients we found 101 patients (20.2%) with persistent elevation of hematocrit value (PTE). It was more frequent in males (82.2% and 17.8% in men and women, respectively). It occurred 2 to 50 months after engraftment (mean value was 11.2 ±8.9 months), majority of PTE which developed in the first 24 months (86%). Spontaneous remission of established PTE was observed in all cases within 3 to 93 months. PTE frequently occurred in patients with well-functioning renal graft, in 82.2% of cases the serum creatinine concentration was less than 1.5 mg/dl and it was 1.5-2 mg/dl in 15.8% of patients. There was no correlation between diabetes mellitus and PTE, compared with control group. PTE was more common in patients who received cyclosporine as compared to those who were not on cyclosporine. In conclusion, Post-transplantation erythrocytosis is a frequent problem in renal transplant patients. Predisposing factors include male gender, retention of native kidneys, cyclosporine consumption and rejection-free course with well-functioning renal graft. PTE is a self-limited complication but can result in thromboembolic disease.