Abstract: Radionuclide renal dynamic imaging(RDI) and intravenous pyelography(IVP) have important roles in evaluation of unilateral renal function. But IVP is affected by renal function. Patients with kidney failure examined by IVP might have poor IVP imaging or even no imaging. So, IVP may underestimate renal function. In these cases, ⁹⁹Tc^m-radionuclide RDI is an ideal method to estimate renal function. It is simple, noninvasive, high sensitivity and recoverable. And it gives notable information such as quantitative unilateral renal function. It is superior to IVP in assessing renal function, and should be performed on kidneys not visualized by IVP.