Hematologic abnormalities including both cytopenias and cytoses are the rule rather than the exception in the first year after kidney transplantation, yet many are benign reflections of immunosuppression, infection prophylaxis, or residual chronic kidney disease. In this Core Curriculum, we distill the evidence on the disorders clinicians encounter most often, cytopenias including neutropenia, lymphopenia, anemia, thrombocytopenia, and thrombotic microangiopathy, as well as cytoses including eosinophilia, lymphocytosis, erythrocytosis, and thrombocytosis.