Abstract. Independent isotopic yields for elements from Zn to La in 25-MeV proton-induced fission of nat U were determined with the JYFLTRAP facility. In addition, isotopic yields for Zn, Ga, Rb, Sr, Zr, Pd and Xe in 50-MeV proton-induced fission of nat U were measured. The deduced isotopic yield distributions are compared with a Rubchenya model, GEF model with universal parameters and the semiempirical Wahl model. Of these, the Rubchenya model gives the best overall agreement with the obtained data. Combining the isotopic yield data with mass yield data to obtain the absolute independent yields was attempted. The result depends on the mass yield distribution.PACS. 24.75.+i General properties of fission -25.85.-w Fission reactions -25.85.Ge Charged-particleinduced fission -28.60.+s Isotope separation and enrichment