Missing holy days of obligation-mortal or venial?

I converted to the Catholic faith a few years ago. I’m still learning the Holy Day of Obligation calendar. This last week I didn’t know it was a Holy Day of Obligation and worked right through the Assumption of Mary Mass. I learned of missing the mass after the fact. Is this a mortal sin I should confess before taking communion? I sometimes still get mixed up about what is considered a mortal sin and what is considered a venial sin and I’m completely confused about this one.

Many Thanks,


Deliberately missing Mass on a Sunday or holy day is a mortal sin if one isn’t ill and can attend, but simply doesn’t bother. But in order to commit a mortal sin, the act must really be sinful, one must KNOW that it is sinful----------and one must freely will it. You didn’t know, so it wasn’t a sin. People often forget about holy days.

Fr. Vincent Serpa, O.P.

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