I took a distribution from my sons' 529 plan to pay some medical expenses for him. I know that I need to report the earnings portion of the distribution as income, but where do I report it?

I took a distribution from my sons' 529 plan to pay some medical expenses for him. I know that I need to report the earnings portion of the distribution as income, but where do I report it?============> 529 plan tax reporting requirements come at the time that your child receives distributions from the plan to pay qualified educational expenses, which generally include tuition and supplies, technology, special needs expenses and room and board. When your child receives distributions from a 529 plan, the amount that you put into the plan is not taxable; it's a return of investment. The earnings from the 529 plan are taxable only if the total distributions are greater than your child's adjusted qualified education expenses. This money is income for your child and reportable on her tax return. If you withdraw money from a 529 plan and do not use it for qualified college expenses( the med. expenses are not a qualified higher education expense under the tax code regardless of the college's requirements or policy options, and it cannot be counted when determining the tax treatment of your 529 plan distributions), you generally have to pay income tax and an additional 10 percent federal tax penalty on earnings;some or all of the distribution was not used for qualifying expenses, then you need to sit down, do some calculations, and arrive at the amount of taxable income you should include on the line labeled "Other Income" on your Form 1040 line 21.

So, long story short, Form 1040 line 21. Thank you.

Is there a different line that the 10% penalty is entered on?

The penalty shows on Line 58 of your Form 1040