The blue grain trait in common wheat (Triticum aestivum L., 2n=6x=42, AABBDD), which is caused by blue pigments in the aleurone layer, was originally derived from the tall wheatgrass (Thinopyrum ponticum Liu & Wang=Agropyron elongatum, 2n=10x=70, StStStStEeEeEbEbExEx) during chromosome engineering research. Over the last few decades, there have been continued interests in the genetic mechanism of this blue coloration and the practical utilization of the blue aleurone character as a phenotypic marker. This article reviews the research history and the recent progress of the studies on blue-grained wheat, with emphases on genetic and biochemical analysis and practical applications of blue-grained wheat.