The radioactive tracer method was used to investigate the adsorption of iodide and europium ions from aqueous solution on dried isoelectric precipitates of silver sulfide, silver iodide and silver bromide. The relationship between the amount of iodide ions adsorbed on Ag2S and the iodide ion and HNO3 concentrations in the solution was determined. It was shown that the iodide ions adsorbed on Ag2S could be desorbed with sulfide ions. Using Ag2S, AgI and AgBr precipitates, a relationship between the europium ion adsorption and Eu(NO3)3, H2S, NaI, NaBr and NaCl concentration in solution was established. The adsorption of europium ions was also assessed in respect to the presence of lanthanum and barium ions. For adsorption measurement iodide and europium ions were labeled with their radioactive isotopes and the amounts adsorbed were determined from the measured radioactivities of the precipitates after reaching the equilibrium between the solid phase and the solution.