Association genetics or association mapping (AM) is one of the approaches that is currently being used because of its multiple applications to many crops. Association genetics is useful as a novel strategy for discovery of new markers to use in marker-assisted selection (MAS) and breeding or for confirmation of quantitative trait loci (QTL). Even though association genetics was defined in the late 1980s, it is only in recent years that this concept has been brought into research practice for plant genetic analysis. The efficient increase of data for genotyping and the increase in computational power have promoted the use of AM. Association genetics offers an interesting approach for genetic analysis of quantitative traits because of its resolution power and the possibility to study various regions of the genome simultaneously without the construction of mapping populations. Thus, AM is a useful option for studying agronomical traits; considering that most agronomic traits are oligo- or multigenic with underlying genes of independent inheritance. The principle of association studies relies on linkage disequilibrium (LD). AM offers a high-resolution power when there is large genotypic diversity and low LD for the germplasm being investigated. This methodology was initially applied in human genetics, especially to understand the genetic basis of many complex traits, especially the inheritance of susceptibility to some diseases. Previously, most quantitative trait analyses for crop species were done exclusively by linkage mapping, but now AM offers an alternative that uses raw germplasm or breeding populations that are of interest to seed bank curators and plant improvement programs. AM has been most widely used in cereals whose wide diversity and low LD have allowed fine mapping of candidate and noncandidate genes. In this chapter, we discuss the advantages and disadvantages of association genetics and mapping especially in dicotyledonous crops of the Fabaceae and Solanaceae with various genome sizes and reproductive strategies (clonal versus sexual). The main objective of this chapter is to highlight the uses of association genetics in major and minor crop species and species that have trouble being analyzed for QTL with classical methods. We discuss the utility of the approach for accelerating breeding in tropical crops, especially in the developing world.