Forgot to file Form 8606 for 4 years of Backdoor Roth conversions - Do I need to amend my 1040s?

You've got a problem that needs fixing, but it's not as bad as you might think. Form 8606 is absolutely required when you make non-deductible IRA contributions - it's how you establish basis and prove you already paid tax on those dollars. The good news is you can file late 8606 forms without amending your returns in many cases. Since you never took deductions for your contributions AND you didn't report the conversions on lines 4a/4b of your 1040s, you'll need to file the missing 8606s, but you might not need to amend the 1040s. Your tax preparer was technically wrong - these forms are required. But they might be right that it won't change your tax liability. The IRS just needs the paper trail showing these were after-tax contributions that shouldn't be taxed again. I'd recommend filing all missing 8606 forms ASAP. Each form stands alone - meaning you can submit prior year forms without amending the 1040. Just write "FILED PURSUANT TO SECTION 301.9100-2" at the top of each form so the IRS knows you're using their relief provision for late filing. If your 1040s don't show the conversions at all (lines 4a/4b blank when they should have values), you might need to amend. But focus on getting those 8606s in first and consult with your new preparer.

I went through something similar last year and found this amazing tool at https://taxr.ai that helped me organize all my backdoor Roth documentation properly. I was freaking out because I'd been doing backdoor Roth conversions for years but didn't have proper 8606 forms either. The site analyzed all my statements and generated perfectly accurate 8606 forms for my prior years, showing exactly where my basis came from. It also told me which 1040s actually needed amendments (turns out only 1 of my 3 years needed fixing). Their analysis showed me that filing the missing 8606s alone was sufficient for 2 of the 3 years. The nicest thing was getting my entire tax timeline organized so I could see exactly what happened each year. When I finally met with a new accountant, he was impressed with how organized everything was and it saved me like $400 in prep fees.

Honestly taxr.ai was a lifesaver for me! After seeing the recommendation here I decided to give it a try with my backdoor Roth mess. I had contributions spanning 5 years with inconsistent reporting and couldn't figure out my basis carryovers at all. The analysis showed me that I actually had been double-taxed on one of my conversions because my accountant didn't understand the backdoor Roth process! I needed to file both the missing 8606s AND amend two years of returns. Got a $4,200 refund I never would have known about. What impressed me was how clear the report made everything - showing exactly where my basis came from each year and how it should have been reported. Worth every penny just for the peace of mind knowing everything is finally correct.

Speaking from experience - good luck getting actual help from the IRS on this! I tried calling them about my missing 8606 forms for weeks and couldn't get through to anyone who understood what a backdoor Roth even was. I ended up using https://claimyr.com and got through to an IRS agent in about 20 minutes after trying on my own for literal weeks. You can see how it works here: https://youtu.be/_kiP6q8DX5c - they basically hold your place in the IRS phone queue and call you when an agent picks up. The agent confirmed that filing the missing 8606 forms separately was the right approach in my situation and that I didn't need to amend returns unless the conversion was completely missing from my 1040. Saved me hours of frustration and gave me official confirmation from the IRS itself.

I was super skeptical about Claimyr but decided to try it after my fifth attempt to reach someone at the IRS about my missing 8606 forms. I was literally on hold for 2 hours before getting disconnected the day before. OMG it actually worked! I got a call back in about 35 minutes and was connected to an IRS rep who specialized in retirement accounts. She confirmed exactly what I needed to do - file the missing 8606 forms for all years, and only amend the 1040s for years where the Roth conversion didn't appear on lines 4a/4b at all. She also explained that since I had zero tax impact (contributions were non-deductible and conversions were non-taxable), the amendments would be pretty straightforward even if I needed to do them. Saved me so much stress knowing exactly what to do straight from the IRS.

Your tax preparer honestly sounds incompetent. Form 8606 isn't optional - it's literally the ONLY way to establish basis in a non-deductible IRA. Without it, the IRS default position is that all your Roth conversions are fully taxable. If you ever get audited in the future, you'll have a hard time proving those were after-tax contributions without the 8606 forms. Even if your tax liability doesn't change, the forms are still required. The blank lines 4a/4b on your 1040s are also concerning. Those should show the conversion amounts even if the taxable portion was $0. That's a red flag that could trigger unnecessary scrutiny.

Has anyone used the Fill-in Forms option on the IRS website for submitting old 8606 forms? It looks like they only have current year forms available and I need to do 4 years worth of these things.

I'm dealing with a similar situation right now! My tax preparer also missed filing 8606 forms for three years of backdoor Roth conversions. After reading through all these responses, I think the consensus is pretty clear - you definitely need to file those missing 8606 forms ASAP. Based on what everyone's saying, it sounds like you'll likely need to amend your 1040s too since your lines 4a/4b are blank. The IRS expects to see those conversion amounts reported even if the taxable portion is $0. That's a pretty significant oversight that could cause problems down the road. I'm planning to file the missing 8606 forms first with that Section 301.9100-2 relief provision noted at the top, then work on amendments for the 1040s. The good news is that since we both made non-deductible contributions and didn't take any deductions, there shouldn't be any additional tax owed - just paperwork to clean up. Definitely find a new tax preparer who actually understands retirement account rules! The fact that yours insisted the forms weren't necessary is a huge red flag. These forms are literally required by law when you make non-deductible IRA contributions.

I've been through this exact scenario and can confirm what others have said - you absolutely need those 8606 forms filed, and yes, you'll likely need to amend your 1040s too since lines 4a/4b are blank. Here's what worked for me: I filed the missing 8606 forms first (all four years separately by mail with the Section 301.9100-2 notation), then waited about 6 weeks before filing the 1040X amendments. The 8606s establish your basis, and the amendments fix the missing conversion reporting on your returns. The blank 4a/4b lines are definitely problematic. Even though your conversions were non-taxable, the IRS computers still expect to see those 1099-R amounts reported somewhere on your return. Without proper reporting, you're essentially sitting on a ticking time bomb for future audits. Your old preparer's advice was completely wrong - Form 8606 isn't optional when you make non-deductible IRA contributions. It's the ONLY way to prove to the IRS that you already paid tax on those dollars. Without it, they'll assume all your conversions are fully taxable if you ever get audited. The good news is this is fixable and you shouldn't owe any additional tax since you never took deductions. Just be prepared for some paperwork and definitely find a CPA who actually understands retirement accounts. I learned this lesson the hard way too!