The aim of this prospective study was to assess the efficacy of using whole-kidney, mean parenchymal and pelvic transit times to evaluate renal function following treatment with extracorporeal shock wave lithotripsy (ESWL). Fifteen patients were evaluated 24-48 h before and after ESWL therapy using Tc-99(m)-DTPA renal scintigraphy. Using deconvolution analysis, whole-kidney, mean parenchymal and pelvic transit times were calculated and the pre-ESWL values were compared with the post-ESWL values. In both kidneys, there were no significant changes in the glomerular filtration rate or relative renal uptake when compared with the pre-ESWL values. The mean whole-kidney transit time of the tracer did not change significantly during the post-ESWL period. In the treated kidney, the mean post-ESWL parenchymal transit time was significantly increased (P<,0.05), while the mean pelvic transit time was significantly decreased (P<,0.05). In the untreated kidney, there were no significant changes in any of these parameters. We conclude that the dual use of parenchymal and pelvic transit times is more sensitive than the mean whole-kidney transit time and other measures, such as glomerular filtration rate and relative renal uptake, for the assessment of outcome of therapy and other related post-ESWL changes.