The effects of prostaglandin $F_2{alpha}$ were investigated on the uterine smooth muscle motility in the pig. The results were summarized as follows : 1. Prostaglandin $F_2{alpha}$ caused the contraction of the porcine uterine smooth muscle and the contractile responses increased between the concentration of prostaglandine $F_2{alpha}$ $10^{-9}$ M and $5{ imes}10^{-8}$ M with a dose-dependent manner. 2. The contractile response induced by prostaglandine $F_2{alpha}$($10^{-8}$ M) was not blocked by pre-treatment with cholinergic receptor blocker, atropine ($10^{-6}$ M). 3. The contractile response induced by prostaglandine $F_2{alpha}$(10$^{-8}$ M) was not blocked by pretreament with ${alpha}$-adrenergic receptor blocker, phentolamine($10^{-6}$ M) and ${eta}$-adrenergic receptor blocker, propranolol($10^{-6}$ M). From these results, it was concluded that the effects of uterine smooth muscle by prostaglandine $F_2{alpha}$ were only the contraction mediated by prostaglandine TEX>$F_2{alpha}$</TEX> receptor in pig, and that it may not be related to the cholinergic and adrenergic receptor.