I understand your plight. Here is what works for me. Go to both. Ask him to go with you to Mass and offer to go with him. As a general rule, Catholics are prohibited only from participating in other forms of worship...but not from attending. There has been many times where the Pope himself has attended other worship services. He does not participate. Understandably, he may not want to participate at Mass. That's fine -- he has no obligation to do so because the law of the Catholic Church does not apply to him. I have explained it this way: As a Catholic, I have people that have authority over me in the spiritual order, primarily my Bishop. Even if I wanted to participate in a Baptist worship service, out of obedience to my Bishop (who expresses the will of the Catholic Church), I will not do so. This explanation is necessary because it shows that your non-participation is not a negative thing but rather a positive thing -- you are trying to be obedient to your Bishop; whom you believe has been granted authority over you in matters of faith. Explain to him that fidelity to the laws of the Catholic Church, to a Catholic, is really synonymous to fidelity to Christ Himself. After all, it is Christ Himself that identifies Himself with the Church (see Acts 9:4). He may not understand this because Baptists do not have this kind of hierarchy and Church Law (aka Canon Law). For the most part, most Baptists believe they are governed by what they think the Bible tells them. Nevertheless, he will appreciate your honesty, your willingness to be obedient to what you believe to be a legitimate authority, and your expressed desire to be faithful to Christ. To answer your question more directly regarding the differences, there are a great deal of difference both in the Mass vs. a Baptist worship service and also in Catholicism vs. the Baptist religion. Before exploring the differences, I would recommend that you consider a "Crash Review in Catholicism" and obtain a deeper understanding of your faith. Here are some good resources: www.catholic.com - Has tracts, articles, forums, etc. A book called "What Catholics really Believe" by Karl Keating ISBN 0-89870-553-3 A book called "Where is that in the Bible?" by Patrick Madrid ISBN 087973693-3 A book, recently back in print, "My Catholic Faith" by Louis LaRavoire Morrow, S.T.D. This is the best Catechism by far for people coming back to the faith. You can find it on amazon.com. Read 1 Pet 3:15 and keep these words of St. Frances in your heart -- "Preach the Gospel always, and if necessary, use words" ...and KEEP PRAYING! God Bless, Jeff