Comparison of eGFR calculated by MDRD and CKD-EPI equations demonstrated no clinically relevant difference. In addition, CKD classification by both equations agreed highly. As both equations performed equally well, the simpler and more established MDRD equation should be preferred in patients with or at high risk of CKD managed in primary care. Patients' characteristics seem to account for previously reported differences in the performance of CKD-EPI and MDRD equations.