Technical Abstract: This book chapter reviews and describes details on the identification of regions on the chromosomes where there is evidence that genes that influence economically important traits reside in beef cattle. The regions where these genes reside are located throughout all the chromosomes. Discussion focuses on growth and carcass traits such as birth weight, weaning weight, yearling weight, slaughter weight, marbling, fat thickness, double-muscling, and meat tenderness. It also includes a detailed account of the genes that have been associated with traits of economical importance. The associations of Myostatin, Leptin, Insulin-like Growth Factor-1, Calpastatin, Thyroglobulin, DGAT1, Growth Hormone, Growth Hormone Receptor, and Calpain with growth and carcass traits are discussed. The potential for using molecular marker information to improve the evaluation of breeds is discussed.