How many times can a lay person receive the Holy Eucharist in a day and why? And is it the same for a priest?

A lay person can receive Holy Communion up to twice in one day (not necessarily a 24 hour timespan, but simply one calendar day). However, the second time receiving Communion that day must be in the context of Mass. You wouldn’t be able to receive the Eucharist if you go to a Communion Service in the evening after attending Mass in the morning.

Furthermore, the Church’s language on the matter says that one should “participate” in the celebration of the Mass when one receives Communion a second time. This doesn’t mean you have to be an altar server or singing in the choir; the way I understand it, the Church is saying that we should be engaging ourselves fully in the Mass: actively participating in the prayers, showing up on time, etc. The only exception would be someone who is in danger of death; Communion can be received as Viaticum in these cases. Also, the other ordinary rules for Holy Communion still apply: you cannot receive Communion if you are in mortal sin, and you must abstain from food and drink for one hour before receiving Communion (excepting water and medicine). You cannot receive Communion more than twice in a single day–the Church’s teaching on this is quite clear.

Priests typically receive Communion more than once a day when they celebrate Mass more than once a day. In order for a Mass to be valid, the priest must receive Communion (under both species). Priests are ordinarily not able to celebrate more than one Mass a day, so under normal circumstances this wouldn’t be a huge issue. However, priests may under certain circumstances celebrate two or even three Masses a day. “If pastoral necessity requires it,” priests can be permitted to celebrate three Masses on a Sunday or Holy Day of Obligation, when there is a shortage of priests (CCL 905.2). He’s also allowed to celebrate three Masses on Christmas and All Souls Day. These exceptions would allow a priest to receive Communion up to three times in a single day (and in fact, he is not even required to abstain for an hour after he has received Communion for the first time that day, since he will usually be pretty short on time)!

These rules are relatively recent for the Catholic Church. Communion twice a day was only allowed for the laity in the 1980s. Before then, it was almost never permitted for a lay person to receive Communion more than once a day. The rule was broadened to its current form to encourage greater devotion to the Eucharist. That being said, it is all the more important for us to not take the Eucharist for granted! What a precious gift to be able to receive Holy Communion at all–how much more so for us to receive Jesus in the Blessed Sacrament every day, or even twice a day! And remember: going to Mass is not the same as receiving Holy Communion. If you go to five Masses in a single day, there are graces for every one of them; however, you are still only able to go to Communion twice.