Question back at you: what exactly do you mean by "ok"? If you mean "Is it possible?" then yes, it is possible. You just have to be careful when you are declaring variables that you explicitly specify which library you want your object to refer to (think "Recordset" object...there's one for ADODB and one for DAO, and they are different).
Dim myDaoRs As DAO.Recordset
Dim myAdoRs As ADODB.Recordset
Also keep in mind that you have to check the appropriate boxes to include the libraries in the Project/References dialog for each of the typelibs.
Another question: why would you want or need to? Is there some kind of functionality that you need that is easier in one than in the other? Are you trying to update an aging app and don't want to hassle with rewriting a bunch of functions? If you are starting a brand-new program, I would recommend choosing one or the other and not mix-and-match. The coding style necessary to effectively use each is substantially different.
Hope this gives you what you were looking for. Good luck!