Odyssée is an automatic differentiation (AD) package developed at INRIA. This tool is able to differentiate a sequential Fortran 77 code with respect to variables chosen by the user. In order to use Odyssée on parallel codes, the class of treatable programs has been extended. We have restrict ourselves to the differentiation of MPI code, but the same methodology can be applied to PVM or any other message passing library. An information base has been defined in order to make the system follow the dependencies between variables, in this way the code is properly analyzed and the generated code is correct. A library of derivative of MPI commands has been written in order to help the user compile and execute the generated code. The implementation of both the information base and the library presented in this documents could be modified by the user to fit his specific needs. We have tested the adapted version of Odyssée on a sample code that uses data partitioning to compute a polynomial. In the Appendix, we present the results obtained on this example. The size of this example allows us to show in the report the whole code. We have tested the adapted version of Odyssée on a pre-industr- ial code NS3D and show the feasibility of the method.