Introduction: Post-transplantation erythrocytosis (PTE) is not well understood and appears to be multifactorial. Up to 25% of patients presented with erythrocytosis after kidney transplantation. Methods: We have performed observation of the rates of erythrocytosis among 37 patients undergoing kidney transplantation from January 2019-December 2021 in Departement of Nephrology, Central General Hospital Dr. Sardjito, Yogyakarta, Indonesia. Outcomes in the selected patients were reviewed and analyzed. Purpose: The purpose of this case series study is to outline the current knowledge of epidemiology and risk factors of PTE in kidney transplantation in Dr. Sardjito General Hospital Yogyakarta. Results: During the observation, 7 people (18,91%) who were diagnosed with PTE with the hematocrit means 56,075 % (in 6 months post-transplant) and 54.07% (in 9 months-Post transplants). All of the patients were without signs and symptoms of thrombosis, had no stroke, no cardiovascular event, and no deep vein thrombosis. All of the patients (100%) who were diagnosed with PTE are male. 71,4% of cases of PTE happen after 6 months post-transplantation. Before transplantation, 57,14% of the patient has a baseline Haemoglobin level above 10 g/dl. Only 1 patient undergoes CAPD before transplantation. All patients have a well-functioning graft with the mean of creatinine 1.35 mg/dl. Patients receiving Ramipril have a reduction of erythrocytosis. Conclusion: PTE is happening in 18,91% of patients, which is comparable to western studies. Most patients develop erythrocytosis after 6 months of transplantation. Good graft function and male gender are the risk factor for PTE in all observations. Almost all patient doesn’t have any symptom of Erytrocytosis since the mean hematocrit level is below 60%. Erythrocytosis responded well to ace inhibitor.