Let $X$ and $Y$ be finite nilpotent CW complexes with dimension of $X$ less than the connectivity of $Y$. Generalizing results of Vigu\'e-Poirrier and Yamaguchi, we prove that the mapping space $\mbox{Map}(X,Y)$ is rationally formal if and only if $Y$ has the rational homotopy type of a finite product of odd dimensional spheres.
Journal of Homotopy and Related Structures, Vol. 5(2010), No. 1, pp. 125-131