The problem is that the tax code is not linear, but rather has step increases in rates. Suppose you are trying to stay in the 15% bracket to take advantage of the favorable capital gains rate this year. Further suppose that $5001 will put you over the top of 15% bracket. Then suppose that next year, your investments have not done as well and it would take $5601 to put you over the top. If there were no RMD's, you could take $5000 out of your IRA this year and $5600 next year without triggering the higher capital gains rate. But now assume that your RMD is $5300. Over two years, you take out exactly the same amount of money, but you pay more tax, because you were captapulted into a higher tax bracket in year one and lost your favorable capital gains rate. When you are forced to take RMD's, it really screws up your tax plannning.