Genomic prediction is an important approach that recently emerged to guide plant and animal breeding efforts. Much of this optimism is based on the success of genomic selection (GS) to predict breeding values, when compared with the traditional results of marker-assisted selection (MAS) and phenotypic evaluations. Its effective implementation depends, however, on important theoretical and practical aspects related to the breeding program composition and the genetic background of the species under investigation. This chapter covers topics related with GS implementation and concepts that underlies its predictive ability. Requirements necessary to the population definition, statistical methods, GS influence on the expected genetic gain, examples of success in tropical crops, and challenges are discussed in order to guide future studies. Finally, we provide a critical analysis about the potential of GS to reshape traditional breeding schemes, without ignoring conventional breeding practices and genetic studies.