This chapter explains the genetic organization of the chloroplast. Chloroplasts are highly complex organelles capable of performing a variety of important tasks. These include primarily the conversion of light energy into chemical energy, which is used to reduce carbon dioxide into carbohydrates. The reducing power generated during photosynthesis is also utilized for the conversion of nitrate and sulfate into organic substances and for the biosynthesis of several amino acids and fatty acids. Chloroplasts possess their own genetic system and protein-synthesizing apparatus, which cooperate closely with the nucleocytoplasm in the biosynthesis of organelles. This chapter highlights those lines of research in chloroplast molecular genetics, which bear on the dual prokaryotic and eukaryotic nature of chloroplasts. Chloroplast genetics is likely to be important for understanding chloroplast gene regulation. Therefore, the chapter describes various attempts at correlating the genetic and physical chloroplast DNA maps.