Electronic Journal of Differential Equations, Vol. 2009(2009), No. 155, pp. 1-7. Title: Existence and uniqueness of solutions to fractional semilinear mixed Volterra-Fredholm integrodifferential equations with nonlocal conditions Author: Mohammed M. Matar Al-Azhar (Univ. of Gaza, Palestine) Abstract: In this article we study the fractional semilinear mixed Volterra-Fredholm integrodifferential equation $$ \frac{d^{\alpha }x(t)}{dt^{\alpha }} =Ax(t)+f\Big(t,x(t), \int_{t_0}^tk(t,s,x(s))ds,\int_{t_0}^{T}h(t,s,x(s))ds\Big) , $$ where $t\in [t_0,T]$, $t_0\geq 0$, $0<\alpha <1$, and $f$ is a given function. We prove the existence and uniqueness of solutions to this equation, with a nonlocal condition. Submitted September 12, 2009. Published December 01, 2009. Math Subject Classifications: 45J05, 26A33, 34A12. Key Words: Fractional integrodifferential equations; mild solution; nonlocal condition; Banach fixed point.