My client has an IRA and owns 100% of a company with a DB in which he is a participnat. May he take 1 RMD from the IRA which covers the RMD amount he must take from both the IRA and the DB Plan? Or, does it depend on what kind of IRA money it is? For example, IRA money that came from a retirement plan?
All help appreciated!!

No. The RMD for the IRA must be taken from the IRA and the RMD for the DB plan must be taken from the plan. See IRS Pubs 590 and 575 at www.irs.gov