Sediment samples from the Tisza River in Serbia were investigated for possible TENORM pollutants. The radionuclide content of the samples was determined by means of low-level high-resolution gamma-spectroscopy. In addition to the members of the natural radioactive chains of (238)U and (232)Th and the natural (40)K, Chernobyl origin (137)Cs was detected in 26 of the 28 samples tested. The higher concentration of (238)U in four locations along the river could be caused by extensive exploitation of phosphate fertilizers in the surrounding agricultural area (TENORM). Also, in one location the lowest (40)K and the highest (232)Th concentration in all samples were detected. Every unexpected distribution is an indication of radioactive contamination.