The present invention relates to a pharmaceutical composition for promoting fertilization comprising cyclic ADP-ribose or its derivative, CD38 and to a method of promoting fertilization by promoting the synthesis of cyclic ADP-ribose to increase sperm motility. Also, the present invention relates to a pharmaceutical composition for contraception and a method for inhibiting fertilization, which can inhibit the expression or function of cyclic ADP-ribose to reduce sperm motility, thereby inhibiting fertilization.