  We study in this short note aging properties of Sinai's (nearest neighbour)
random walk in random environment. With $\PP^o$ denoting the annealed law of
the RWRE $X_n$, our main result is a full proof of the following statement due
to P. Le Doussal, C. Monthus and D. S. Fisher: $$\lim_{\eta\to0}
\lim_{n\to\infty} \PP^o (\frac{|X_{n^h} - X_n|}{(\log n)^2} < \eta) =
\frac{1}{h^2} [ {5/3} - {2/3} e^{-(h-1)} ]. $$
