The c locus of Zea mays, involved in the regulation of anthocyanin biosynthesis, has been cloned by transposon tagging. A clone (# 18En) containing a full size En1 element was initially isolated from the En element-induced mutable allele c-m668655. Sequences of clone # 18En flanking the En1 element were used to clone other c mutants, whose structure was predicted genetically. Clone #23En (isolated from c-m668613) contained a full size En1 element, clone #3Ds (isolated from c-m2) a Ds element and clone # 5 (isolated from c+) had no element on the cloned fragment. From these data we conclude that the clones obtained contain at least part of the c locus. Preliminary data on transcript analysis using a 1-kb DNA fragment from wild-type clone # 5 showed that at least three transcripts are encoded by that part of the locus, indicating that c is a complex locus.