  Mahmoodian and Soltankhah $\cite{MMS}$ conjectured that there does not exist
any $t$-$(v,k)$ trade of volume $s_{i}< s <s_{i+1}$, where
$s_{i}=2^{t+1}-2^{t-i}, i=0,1,..., t-1$. Also they showed that the conjecture
is true for $i=0$. In this paper we prove the correctness of this conjecture
for Steiner trades.
