Lentils, despite their tremendous importance as a human food, an animal feed, and in rotational cropping systems, have remained under-exploited and poorly researched. Although some traditional cytogenetic techniques have aided in our understanding of the lentil genome, the organization and structure of the genome remains largely undiscovered. Understanding the genetic potential of both cultivated and wild lentils is essential for mining useful genetic variations, as well as for adding considerable resources to lentil breeding programs. This chapter addresses the knowledge on available lentil genomics derived through traditional cytogenetics and the potential to improve our understanding through applications of modern cytogenetic manipulations, including the use of fluorescence in situ hybridization (FISH), genome in situ hybridization (GISH), and distant hybridization, coupled with embryo ovule rescue and haploid breeding to widen the genetic resources of lentil.