Grass lignins are made of guaiacyl and syringyl units together with minor amounts of p-hydroxyphenyl units. The specific association of p-coumaric (pCA) and ferulic (FA) acids to grass lignins has suspected important consequences on wall properties which are however, poorly understood. Genetic variation for lignin content, lignin structure, and p-coumaric and ferulic acid contents has been shown in normal maize, after an earlier description in brown-midrib (bm) mutants. QTL analyses for lignin-related traits have established that nearly 40 genomic regions are involved in maize variation of lignin content. For most of these locations, no candidate genes have been validated, or have been still defined. Whereas all steps of lignin biosynthesis have been presumably identified, little is known about the number of gene members encoding each enzymatic step and the role of each member in organ, stage and/or tissue specificity. Moreover, even if the lignin pathway has often been displayed as a metabolic grid, available results, especially in maize bm and genetically engineered plants, suggest that the hydroxylation/methylation steps at the aromatic C-3 position have a key role in controlling the flux to lignins. Recent studies of cell wall-related gene expression in young and silking maize plants also illustrated an unexpected diversity of genes with differential expression profiles, especially in bm mutants. Breeding maize and other grasses for phenolic structures more suitable for animal nutrition or energy production could now be considered a realistic goal by integrating new genomic-based knowledge on maize lignification. ___________________