The keeping quality of cut flowers, during the postharvest stages, is very important in the global market, where floricultural items must be extremely competitive. Postharvest physiological analyses of senescence point to plant hormones playing important roles in the promotion or inhibition of flower and leaf senescence. Among them, ethylene and abscisic acid (ABA) are the most important. Ethylene has been extensively studied and much information is available for modulating senescence in ethylene-sensitive flowers. In contrast, the role of ABA during cut flower senescence has been wrongly assigned secondary importance. In this chapter, the effect of ABA on leaf and flower senescence has been briefly reviewed in select species, with a brief discussion of ABA and gene expression.