My son pays rent for his room and board. Do I have to do a Sch C to report this?

[M-MTax]

Report it on Sch E if at all. You could treat it as expense sharing and not even report it.

[xmasbaby0]

Do you mean your son is paying rent to you to live in your home?   If this is simply family cost sharing then there is nothing to enter on a tax return about it.   Or do you have some sort of written rental/lease agreement with your son?   Please explain what is going on so we can be more helpful.

[Opus 17]

If you want to treat the rent as a business, and you are charging a fair market level of rent (the same as you would charge a stranger to rent a room with kitchen privileges and whatever else), then you could consider reporting it on schedule E (not C).  However, if you are not charging a fair market rent, there is really no benefit to going to all the trouble.  In the case of family sharing expenses, there is no requirement to treat family as a business (unless you want to).