Electronic Journal of Differential Equations, Vol. 2007(2007), No. 49, pp. 1-13. Title: Positive periodic solutions for the Korteweg-de Vries equation Author: Svetlin Georgiev Georgiev (Univ. of Sofia, Bulgaria) Abstract: In this paper we prove that the Korteweg-de Vries equation $$ \partial_t u+\partial_x^3 u+u\partial_x u=0 $$ has unique positive solution $u(t, x)$ which is $\omega$-periodic with respect to the time variable $t$ and $u(0, x)\in {\dot B}^{\gamma}_{p, q}([a, b])$, $\gamma>0$, $\gamma\notin \{1, 2, \dots\}$, $p>1$, $q\geq 1$, $a0$ is arbitrary chosen and fixed. Submitted January 18, 2006. Published April 4, 2007. Math Subject Classifications: 35Q53, 35Q35, 35G25 Key Words: Nonlinear evolution equation; Kortewg de Vries equation; periodic solutions.