  A slope $\frac pq$ is called a characterizing slope for a given knot $K_0$ in
$S^3$ if whenever the $\frac pq$-surgery on a knot $K$ in $S^3$ is homeomorphic
to the $\frac pq$-surgery on $K_0$ via an orientation preserving homeomorphism,
then $K=K_0$. In this paper we try to find characterizing slopes for torus
knots $T_{r,s}$. We show that any slope $\frac pq$ which is larger than the
number $\frac{30(r^2-1)(s^2-1)}{67}$ is a characterizing slope for $T_{r,s}$.
The proof uses Heegaard Floer homology and Agol--Lackenby's 6--Theorem. In the
case of $T_{5,2}$, we obtain more specific information about its set of
characterizing slopes by applying more Heegaard Floer homology techniques.
