Reliability issues play a relevant role in the design of embedded systems for critical ap- plications; this and the always increasing performance requirements lead to the adoption of new architectural solutions, as shown by the introduction of Multi-Processor Systems-on- Chip (MPSoC). MPSoCs raise new challenges related to the complexity of the interactions among several independent cores. This paper presents a framework, based on a simulation platform, for the design of this kind of embedded systems; the framework supports the use of reliability techniques in order to address fault detection and tolerance issues. The simu- lation platform is also adopted for a reliability assessment task, achieved by exploiting fault injection targeting each component of the system and by monitoring the effects on the entire architecture.