Are you able to patch a Terra Cotta pipe that has a crack in it, with cement to keep water from leaking out of it? Will cement adhere to terra cotta?

There are a variety of adhesives/sealants that will stick OK, but you're better off replacing the damaged section - especially if you had to dig to expose it.

If it's something that's always exposed, it certainly couldn't hurt to try a patch job on it since it's easy to get to.

From pm

The pipe is underground in basement however it leads to outside and if removed will need to dig outdoors also or could possibly break other pipes in removal process. I would like to prevent having to dig outdoors, what is a good adhesive that would stand up to seal leak? Or do you highly reccommend replacement?

Darlene, yes, I highly recommend replacement.

The last thing you want to do is have to dig it up again later.

I do believe that you should be able to cut out the bad part and use a combination of rubber fittings and pvc to replace the bad part, but stand by for input from our plumbing expert who is far more knowledgeable than I.