Casein kinase II activities in crude homogenates from mucosa, adenomas and colorectal carcinomas were determined. 20 patients were studied. CKII activity was elevated in the adenomas and carcinomas when compared to the mucosa. The highest CKII activities ranging from 16–113 U/mg protein were found in colorectal carcinoma tissue. These concentrations were markedly different in normal mucosa tissue (2–33 U/mg protein). CKII activity in adenoma tissue showed an intermediate activity ranging between 5–63 U/mg protein. The differential CKII activities in mucosa, adenoma and carcinoma tissue supports the notion of an adenoma carcinoma seq