Zajdela ascitic hepatoma cells are shown to take up pyrimidine bases at much lower rates than obtained in slices from normal rat liver. The rates of uptake of adenine and uridine by the Zajdela cells are, however, as high as in the slices. Like the slices, again, the Zajdela cells take up E. coli RNA and DNA at very low rates but, unlike the slices, thses cells degrade rapidly the RNA taken up. The Zajdela cells resemble parenchymal cell suspensions derived from normal rat liver in regard to the uptake of pyrimidine bases and the ability to degrade heterologous RNA.