The cytokinin activity of 8 previously unstudied diphenylurea (DPU)derivatives, differing in either type or position of the substituents of thephenyl rings, was investigated. Cytokinin activity was assessed using thebetacyanin (so-called amaranthin) accumulation test and the tomato regenerationtest. We also assayed their capacity to enhance adventitious root formation inmicrocuttings of apple rootstock M26 and in a tomato cotyledon rooting test,while their possible auxin-like activity was tested using the pea stemelongation test. All the compounds showed weak cytokinin activity, and thismight be responsible for the enhanced adventitious rooting which is induced bysome of the compounds. None of the DPU derivatives showed auxin-like activity.