  This paper deals with new sequence spaces $X(r, s, t ;\Delta) $ for $X\in
\{l_\infty, c, c_0\}$ defined by using generalized means and difference
operator. It is shown that these spaces are complete normed linear spaces and
the spaces $X(r, s, t ;\Delta)$ for $X\in \{c, c_0\}$ have Schauder basis.
Furthermore, the $\alpha$-, $\beta$-, $\gamma$- duals of these sequence spaces
are computed and also established necessary and sufficient conditions for
matrix transformations from $X(r, s, t ;\Delta)$ to $X$.
