Synchronizing sequences have been proposed in the late 1960s to solve testing problems on systems modeled by finite-state machines. Such sequences lead a system, seen as a black box, from an unknown current state to a known final one. This paper presents a first investigation of the computation of synchronizing sequences for systems modeled by synchronized Petri nets. In the first part of the paper, existing techniques for automata are adapted to this new setting. Later on, new approaches, that exploit the net structure to efficiently compute synchronizing sequences without an exhaustive enumeration of the state space, are presented.