To investigate whether brassinosteroids (BR) affects cytokinin (CK)-induced anthocyanin biosynthesis, seedlings of the Arabidopsis dwarf4 ( dwf4 ) mutants including partially suppressing coi1 ( psc1 ) and dwf4-102 , which are defective in the BR biosynthesis, and the brassinosteroid-insensitive 1–4 ( bri1-4 ) mutant defective in BR signalling were used for the analysis of CK-induced anthocyanin accumulation and the expression of anthocyanin biosynthetic genes and WD-repeat/Myb/bHLH transcription factors. The results show that the CK-induced anthocyanin accumulation was remarkably reduced in dwf4 and bri1-4 mutants, but distinctly increased in the wild type (WT) treated with BR. Moreover, the CK-induced expressions of the late anthocyanin biosynthetic genes including dihydroflavonol reductase , leucoanthocyanidin dioxygenase , and UDP-glucose: flavonoid-3-O-glucosyl transferase were significantly reduced in bri1-4 and dwf4-102 mutants compared to WT. In addition, the expressions of transcription factors production of anthocyanin pigment 1 ( PAP1 ), glabra 3 ( GL3 ), and enhancer of glabra 3 ( EGL3 ) were induced by CK in WT but not in the bri1-4 and dwf4-102 mutants. These results indicate that BR enhanced the CK-induced anthocyanin biosynthesis by up-regulating the late anthocyanin biosynthetic genes and this regulation might be mediated by the transcription factors PAP1 , GL3 , and EGL3 .