We present our newly developed Mathematica package HolonomicFunctions which serves for automatic finding and proving of holonomic function identities. The class of holonomic functions includes most of the elementary functions (like sine, exponential, logarithm, algebraic expressions, etc.) and the majority of so-called special functions (like Bessel functions, orthogonal polynomials, hypergeometric functions, etc.). The package adresses both summation and integration problems.