The comparative pharmacokinetic study of PAHIDA-99mTc p-(biscarboxymethyl)-aminomethylcarbaminohipuric acid, MAG3-99mTc (mercaptoacetyltrigly cine) and DTPA-99mTc (diethylenetriaminepentaacetate) was made by measurement of biodistribution, blood clearance, volume distribution, half-lives of distribution and elimination, and other relevant parameters. The percentage of protein binding was determined too, by the methods of dialysis and precipitation. These results were used to calculated the constants and rates of protein binding. The results of biodistribution show that MAG3-99mTc exibits a higher in the same time interval. The present work also reports results of clinical investigation of PAHIDA-99mTc.