The announcement from the moderate Massachusetts senator makes passage of the amendment even less likely, after the Senate initially voted it down as part of a broader budget bill earlier this month.
Rep. Mike Pence, R-Ind., has pushed the amendment hard, particularly in the wake of undercover videos that appeared to show Planned Parenthood workers offering advice to actors posing as a pimp and prostitute. The ban was one of several GOP-sponsored riders attached to a budget bill for the rest of the year that cleared the House but died in the Senate, sending both sides back to the drawing board.
The federal government currently is operating on a three-week budget bill, and Brown said both sides will have to compromise going forward.
"I support family planning and health services for women. Given our severe budget problems, I don't believe any area of the budget is completely immune from cuts," Brown said in a statement. "However, the proposal to eliminate all funding for family planning goes too far. As we continue with our budget negotiations, I hope we can find a compromise that is reasonable and appropriate."
Federal law prohibits taxpayer dollars from funding abortions, but pro-life lawmakers for years have tried to strengthen restrictions to ensure funding for non-abortion purposes does not mingle with or inadvertently boost funds for abortion services.
According to a Government Accountability Office study last summer, Planned Parenthood tapped into $657 million in federal dollars between 2002 and 2009.