“If not in a community state, can one person filing MSF take all of the itemized deduction (all that have their SS# attached to it) and the other take none (and no standard deduction)? Can you take the itemized deductions that are normally available jointly (mortgage interest, donations, etc.) and assign them to one person instead of splitting them 50/50, if not in a community property state?”---->Not really. If you file married filing separately, you must divide the itemized deduction between yourselves. As you can see, the itemized deductions cannot be taken twice. They should be itemized by the one to whom they apply and who actually paid them. For example, if there are medical deductions, each takes his/her own. If ONLY you made a charitable contribution out of your funds, ONLY you deduct it. Joint obligations made from common funds are divided, usually equally. In addition, you, as MFS taxpayers, must both claim the standard deduction or must both itemize their deductions; what I mean is that one MFS filer cannot claim the standard deduction if the other spouse is itemizing.