The chloroplast is a unique organelle in photosynthetic eukaryotes, essential for fulfilling the complex and diverse functions required in green plant tissues. To support these functions, chloroplasts must be fully developed and operational. Their development is regulated by an intricate network of external and intrinsic factors. Despite the necessity of functional chloroplasts, many plant species exhibit variegated phenotypes characterized by leaves containing pale green, yellowish, or white segments, which often lack functional chloroplasts. The physiological and ecological advantages of this phenomenon remain unclear, as leaf variegation is typically perceived as detrimental to optimal photosynthetic efficiency. However, under specific adverse environmental conditions, the adaptive benefits of variegation may outweigh the drawbacks associated with the absence of fully developed chloroplasts. To gain a deeper understanding of the molecular origins and physiological implications of variegation, it is essential to investigate the ultrastructure of plastids in non-photosynthetically active leaf cells under physiological and various stress conditions. Therefore, this chapter focuses on the histological differences between the mesophyll tissue of uniformly green leaves and the yellow or white sectors of variegated leaves. Numerous ultrastructural studies suggest that the plastids in the non-green leaf sectors represent a distinct type of plastid, referred to as “albinoplasts.” The primary objective of this chapter is to highlight the key ultrastructural differences between normal plastids and the albinoplasts observed in the non-green leaf sectors. This analysis considers a broad spectrum of molecular factors contributing to variegated phenotypes in both dicotyledonous and monocotyledonous plant species.