The regulatory genes encode transcription factors that regulate expression of structural genes in anthocyanin biosynthesis pathway in rice. In this study, cloning of a regulatory OsC1 gene, encoding a Myb transcription factor, from young leaves of white, red and black rice varieties was performed by PCR. The cloned full-length OsC1 genes were analyzed by comparison of their nucleotide sequences and deduced amino acid sequences with those in GenBank. It was found that the cloned full-length OsC1 genes had 1,292 bp in length containing 3 exons and 2 introns. In white and red rice varieties, the genes contained 10-bp deletion in the 3rd exon, resulting in a frameshift mutation, the occurrence of a premature stop codon, and truncated polypeptides. Moreover, the base substitutions were detected in white and red rice varieties, causing amino acid substitutions at a few positions. These frameshift mutation and base substitutions affecting the region of DNA-binding domain of R2R3 region of Myb transcription factor might result in non-function of the OsC1 gene in white and red rice varieties and no pigmentation of anthocyanins. Expression analysis of regulatory OsC1 gene by RT-PCR revealed that the tested white, red and black rice varieties showed expression of OsC1 gene in young leaves and developing seeds, suggesting that OsC1 gene might play an important role in regulation of anthocyanin biosynthesis in leaves and seeds. The cloned OsC1 gene from rice variety, Kam, with dark purple/black pericarp was made of the gene cassette under the control of dual 35s Promoter and nos Terminator. The gene cassette was then constructed into binary vector, pCAMBIA1305.1 which has gus and hptII as reporter gene and selectable marker gene, respectively. The construct was transformed into Agrobacterium tumefaciens, strain EHA105 for rice transformation. The research has been continued and supported by the grant of 2018 from the Office of Agricultural Research and Extension, Maejo University. The OsC1 has been transformed into rice in order to study function of the gene and the interaction of two regulatory genes, which are OsC1 and OsB2 in regulation of anthocyanin biosynthesis. The understanding of structure of regulatory genes in anthocyanin biosynthesis in white and colored rice varieties will be beneficial in use as marker genes for improvement of rice by molecular breeding and genetic engineering in the future.