Although there are numerous studies in the literature which quantified renogram curves in various respects, relative uptake in relation to perfusion pattern has not been evaluated on Tc-99m DTPA time-activity curves. In a previous study, we observed sequential changes of this pattern in renal transplant donors. In this study, we evaluated this pattern in kidneys with varying degrees of renal function. The aim was to reveal the pathophysiologic significance of perfusion/uptake pattern on Tc-99m DTPA renal scintigraphy. In order to evaluate uptake in relation to perfusion pattern on Tc-99m DTPA time-activity curve, we have studied serial changes in 2 different patient groups: A. Renal transplant donors before, early after and months after nephrectomy; B) Renal transplant recipients early after transplantation, at the initial stages of chronic allograft nephropathy (CAN) with proteinuria, and at later stages of CAN. Quantitative scintigraphic parameters included: the ratio of peak perfusion to plateau on the perfusion part of the curve (P:PL), the ratio of peak perfusion to that of peak uptake (P:U), the ratio of peak uptake to plateau (U:PL), time to maximum uptake (Tmax). Each group in the study exhibited a different pattern of time-activity curve. Based on our results we classified the curves into 5 pattern. Compared to preoperative findings, P:U increased significantly early after donor nephrectomy. The same value decreased months after nephrectomy. In patients at the early stages of CAN, P:PL was significantly lower than that obtained early after transplantation. At later stages of CAN, perfusion and uptake peaks were absent. The findings observed in renal transplant donors indicate that serial changes in uptake/perfusion pattern in kidneys with normal function might be an indicator of renal reserve capacity. Intraglomerular pressure is known to be high in patients with proteinuria and it increases as renal failure progress. Serial changes in perfusion/uptake pattern in patients with CAN might imply changes that reflect intraglomerular pressure. These findings remains to be confirmed with further studies.