As with most legal questions, there is a short and simple answer to this question and a longer, more in-depth answer. The short answer is yes. Like other funds, alimony must be reported on federal tax returns as a source of income regardless of how spousal support is determined. The longer part of the answer is simply a clarification of requirements that make these payments alimony for tax purposes.
-- You and your ex file separate tax returns-- Your divorce, maintenance decree or separation agreement does not contain language indicating that the payments are not alimony-- You receive the payments from a spouse or a former spouse-- You and your spouse do not share the same household at the time the payments are received-- The funds you receive have not been earmarked as a property settlement or as child support
The alimony you are receiving is considered income whether you receive the funds as part of a divorce decree or as part of a separation agreement. As such, it must be declared on your tax return even if you are not yet divorced. It is also important to note that if you and your spouse still file joint taxes for any reason, the spouse paying alimony cannot declare the payments on his or her tax return.
The financial elements of a divorce can be confusing, especially during the first few years. In order to avoid unnecessary financial trouble, sometimes those newly divorced like to talk with an attorney about the requirements of filing tax returns. A legal team can be a good resource for newly divorced couples who have questions or concerns about the financial aspects of divorcing.
Source: IRS.gov, "Topic 452 - Alimony Paid," accessed Sep. 02, 2015