Patient: Female, 51Final Diagnosis: Tacrolimus induced severe neutropeniaSymptoms: Abnormal lab valuesMedication: —Clinical Procedure: —Specialty: TransplantologyObjective:Adverse events of drug therapyBackground:Renal Transplant recipients are at risk for developing neutropenia from a multitude of causes. The cause is often multifactorial, and reversal of the most common causes/insults is sometimes insufficient.Case Report:We present the case of a renal transplant recipient who developed a prolonged course of post-transplant (PTx) neutropenia that resolved after switching from tacrolimus (tac) to cyclosporine (CsA).Conclusions:Transplant recipients with persistent neutropenia, sometimes despite discontinuation of potential myelosuppressive agents like mycophenolic acid (MPA), valganciclovir, and sulfamethoxazole-trimethoprim (SMZ-TMP), and with introduction of granulocyte colony-stimulating factor (G-SF), and ruling out alternative diagnoses, may benefit from changing from tac to CsA.