Isolated nucleic acid molecules encoding human c-Maf, and isolated c-Maf proteins, are provided. The invention further provides antisense nucleic acid molecules. recombinant expression vectors containing a nucleic acid molecule of the invention, host cells into which the expression vectors have been introduced and non-human transgenic animals carrying a human c-Maf transgene. The invention further provides human c-Maf fusion proteins and anti-human c-Maf antibodies. Methods of using the human c-maf compositions of the invention are also disclosed, including methods for detecting human c-Maf activity in a biological sample, methods of modulating human c-Maf activity in a cell, and methods for identifying agents that modulate the activity of human c-Maf.