We have isolated and characterized cellular kinases which associate with the transactivation domain of c‐Myc and phosphorylate Ser‐62. We demonstrate that cellular Map kinases associate with c‐Myc under stringent conditions and phosphorylate Ser‐62. We also find that TPA stimulates the activity of the Myc‐associated Map kinase to phosphorylate Ser‐62. However, we do not observe an increase in Ser‐62 phosphorylation in endogenous c‐Myc after TPA treatment of cells. Since the regulation of the c‐Myc‐associated Map kinases does not correlate with the in vivo regulation of Ser‐62 phosphorylation in c‐Myc, we conclude that Map kinases are not the in vivo kinases for Ser‐62. Although Ser‐62 phosphorylation was not affected by TPA, phosphorylation at a different serine residue was significantly upregulated by TPA. J. Cell. Biochem. 72:483–491, 1999. © 1999 Wiley‐Liss, Inc.