  This paper describes a package for calculations of expressions with Dirac
matrixes. Advantages to existing similar packages are described. MatrixExp
package is intended for simplification of complex expressions involving
$\gamma$-matrixes, providing such tools as automatic Feynman parameterization,
integration in $d$-dimensional space, sorting and grouping of results in a
given order. Also, in comparison with existing similar package Tracer,
presented package MatrixExp has more enhanced input possibility. User-available
functions of MatrixExp package are described in detail. Also an example of
calculation of Feynman diagram for process $b\to s\gamma g$ with application of
functions of MatrixExp package is presented.
