Abstract: The data obtained from the radioassay of fish collected in vicinity of the Hanford Works between April, 1948 and June, 1950 are presented. Most of the radioactivity in the fish resulted from the concentration of p32 in the scales, bone, and certain visceral organs. The level of activity density in the fish was influenced by size, feeding habits and metabolic rate in addition to the activity density of the water. Changes in operation of nuclear reactors have resulted in progressive increases in activity densities of fish from one year to the next. The levels of radioactivity are not sufficiently high to be hazardous to either the fish or persons eating them.