  Let $G$ be a $t$-tough graph on $n\ge 3$ vertices for some $t>0$. It was
shown by Bauer et al. in 1995 that if the minimum degree of $G$ is greater than
$\frac{n}{t+1}-1$, then $G$ is hamiltonian. In terms of Ore's conditions in
this direction, the problem was only studied when $t$ is between 1 and 2. In
this paper, we show that if the degree sum of any two nonadjacent vertices of
$G$ is greater than $\frac{2n}{t+1}+t-2$, then $G$ is hamiltonian.
