Area covered: These drugs, particularly calcineurin inhibitors, have very narrow therapeutic windows, i.e., they have numerous drug-related side effects. Herein, we focus on the most frequent immunosuppressive drug-related side effects that we encounter in kidney-transplant recipients: namely nephrotoxicity, post-transplant diabetes mellitus, leukopenia, anemia, dyslipidemia, mouth ulcers, hypertension, and viral reactivations (cytomegalovirus and BK virus). However, other therapies that are used after kidney transplantation, e.g., valcancyclovir, may also contribute to adverse events such as leukopenia. For each side-effect, we suggest how it can be prevented and how to treat it when present.