Extracts of [human cervical carcinoma] HeLa cell fractions were analyzed by DEAE- and phospho-cellulose chromatography for their range of cAMP-dependent and -independent protein kinase activities phosphorylating histone and/or phosvitin; extractions were by phosphate buffered saline (soluble protein kinases) and the non-ionic detergent NP-40 (membrane-bound protein kinases). The soluble fraction contained cAMP-dependent histone kinases type I and II as evidenced by their behavior on DEAE-cellulose and inhibition by the specific heat- and acid-stable protein kinase inhibitor (PKI) in a dose-related manner; both types I and II as well as their purified catalytic subunit also phosphorylated protamine and, with very low efficiency, casein but not phosvitin; a histone kinase (H), insensitive to cAMP and PKI, also accepting protamine as substrate but not either casein or phosvitin; a phosvitin kinase (P), insensitive to cAMP and PKI, which also phosphorylates casein but not histone or protamine. These 4 enzyme species were also found in NP-40 extracts of 27,000 .times. g residues which contained further histone and phosvitin kinase activities as yet unspecified. NP-40 extracts of the microsomal fraction possessed, besides unspecified histone and phosvitin kinase activity, only the phosvitin kinase P and appeared to be devoid of histone kinases I, II and H. The occurrence and ratios of the protein kinases classified suggest an ordered distribution over the diverse subcellular fractions of HeLa cells. The overall pattern of soluble and membrane-bound histone and phosvitin kinases in extracts of cervix carcinoma tissue, the in vivo correlate of HeLa cells, closely resembled that of similar extracts of HeLa cells hence appear, despite their long in vitro history, to express protein kinase activities similar to those of their in vivo ancestors, recommending them as a subject for the study of (certain) human protein kinase systems.