pdftex

You can use \colorbox and an escape character inside your listing: Add to your preamble \usepackage{color} \definecolor{light-gray}{gray}{0.80} then use it like this in your document: \begin{lstlisting}[escapechar=!] def mult(m: Matrix[Int], n: Matrix[Int]) { val p = !\colorbox{light-gray}{new MatrixInt}!(m.rows, n.cols) } \end{lstlisting}