Abstract: Polyamines are physiologically active materials with broad functions of regulation, and have a close relationship with the growth and development of higher plants. This paper reviews the relationship between endogenous polyamines and floral bud induction and sex differentiation, flowering, fruit setting and fruit development in higher plants. Effects of exogenous polyamines on flowering a n d fruit setting and development are also reviewed. Both the modes of action and potential applications of polyamines on higher plant in flowering and fruit setting and development are discussed.