Oxidative cross-coupling of phenolic polymers, mainly poly(bisphenol A) including poly(m-cresol) and poly(p-tert-butylphenol), onto a phenol-containing cellulose has been performed in pyridine at room temperature under air to produce cellulose-phenolic polymer hybrids, cellulose-graft-phenolic polymers, which is a new synthetic method utilizing phenolic polymers as substrates. Iron salen complex and hydrogen peroxide were used as a catalyst and an oxidizing agent, respectively. During the reaction, the cross-coupling between the cellulose derivative and the phenolic polymer as well as the homocoupling of the phenolic polymer took place. The resultant cellulose-phenolic polymer hybrid was isolated by reprecipitation. Characterization of the hybrid was performed by H-1 NMR, SEC, UV, and elemental analysis. The coupled amount of the phenolic polymer on the cellulose could be controlled by the feed ratio. The present study provides a new method for hybrid polymer synthesis by oxidative coupling, leading to production of a new type of biopolymers from abundant renewable resources.