  Using the standard square--function method (based on the Poisson semigroup),
multiplier conditions of H\"ormander type are derived for Laguerre expansions
in $L^p$--spaces with power weights in the $A_p$-range; this result can be
interpreted as an ``upper end point'' multiplier criterion which is fairly good
for $p$ near $1$ or near $\infty $. A weighted generalization of Kanjin's
\cite{kan} transplantation theorem allows to obtain a ``lower end point''
multiplier criterion whence by interpolation nearly ``optimal'' multiplier
criteria (in dependance of $p$, the order of the Laguerre polynomial, the
weight).
