Top negotiators for both sides met for more than seven hours Monday, returning to bargaining about 14 hours after ending talks Sunday night.
The sides are in disagreement over how to split basketball-related income.
Stern said both sides are "very far apart on virtually all issues. ... We just have a gulf that separates us."
The owners have locked out the players since July 1. Last week the entire pre-season was canceled.
Opening night was scheduled for Nov. 1.
The Associated Press contributed to this report.