Can Roman Catholics receive communion in the Eastern Orthodox Church and vice-versa?
Currently, the Roman Catholic Church allows Orthodox Christians to commune at their services. In the United States, this is stated on the inside page of most missalettes with the statement:
“Members of the Orthodox churches, the Assyrian Church of the East, and the Polish National Catholic Church are urged to respect the discipline of their own churches. According to Roman Catholic discipline, the Code of Canon Law does not object to the reception of Communion by Christians of these churches (canon 844 § 3).”
However, Orthodox Churches do not allow inter-communion in recognition of the fact that there is currently no Eucharistic (or dogmatic) unity between the Roman Catholic and Orthodox Churches. Moreover, Orthodox bishops do not allow the members of their flock to receive Communion at Roman Catholic services, except for truly unique circumstances. This is why the Roman Catholic statement cited above insists that Orthodox Christians are “urged to respect the discipline of their own churches.”
There have been some notable exceptions to these rules. In the nineteenth-century Russia, for example, Orthodox priests were allowed to give Communion to Roman Catholics in emergency situations if there was no Roman Catholic priest available. In the 1970s, Russian Orthodox Metropolitan Nikodim of Leningrad temporarily allowed intercommunion with the Roman Catholic Church within the borders of his diocese. The rare and very controversial practice, however, did not become widespread and was eventually terminated.
Perhaps, the best summary of the current situation in the United States comes from a 1969 statement agreed upon by the North American Orthodox-Catholic Theological Consultation: “…we are aware that serious differences exist in our understanding of the church, eucharistic discipline, and pastoral practice which now prevent us from communicating in one another’s churches.” Even though this document is more than forty years old, it still reflects the Orthodox consensus on this issue.