Kid1 encodes a transcriptional repressor implicated in the differentiation of renal epithelial cells. Here we report the characterisation of Kid3, a novel mouse gene related to Kid1. Kid3 encodes a C2H2 zinc finger protein with an N-terminal KRAB transcriptional repression domain. It maps to chromosome 11, adjacent to Kid1 and another related gene Kid2. Northern analysis shows that Kid3 is highly expressed in embryonic and adult brain, with lower levels in adult and embryonic (E16.5) kidney, gut, lung and heart. Expression of Kid3 in the kidney is developmentally regulated and suggests a role for Kid3 in the early stages of nephrogenesis.