[Xaviax]

I don't know maybe someone else has experience with their warranty. Some things I buy require product registration to be eligible for the warranty and others don't so I'm never sure.
 
P.S. the headphones sound great <3

 

[zyzyx]

Typically registration isn't a legal requirement for warranty eligibility and is more of a marketing tool. I know that to be the case in California and several other states. Not quite confident enough to make an across the board generalization, but you're probably safe.

 

[Synergy Sound]

All you need for your Sennheiser warranty is proof of purchase and care for your 598s.