Seven million Americans are at least 90 days behind on their car payments, the Federal Reserve Bank of New York reported Tuesday.
The number marked a record.
Economists said it was troubling to see the number rise higher than it was following the financial crisis a decade ago despite today's low unemployment and growing economy.
"The substantial and growing number of distressed borrowers suggests that not all Americans have benefited from the strong labor market," New York Fed economists wrote in a blog post.
Car delinquencies are considered a sign of real financial trouble, because people need their vehicles to get to work, and can live out of them if they lose their homes.
"Your car loan is your No. 1 priority in terms of payment," said Michael Taiano, a senior director at Fitch Ratings.